Binary cmdlet binding fails to unwrap a scalar PSObject for StringCollection parameters

### Prerequisites

- [x] Write a descriptive title.
- [x] Make sure you are able to repro it on the [latest released version](https://github.com/PowerShell/PowerShell/releases)
- [x] Search the existing issues.
- [x] Refer to the [FAQ](https://github.com/PowerShell/PowerShell/blob/master/docs/FAQ.md).
- [x] Refer to [Differences between Windows PowerShell 5.1 and PowerShell](https://learn.microsoft.com/powershell/scripting/whats-new/differences-from-windows-powershell).

### Steps to reproduce

```pwsh
$source = @'
using System.Collections.Specialized;
using System.Management.Automation;

[Cmdlet("Test", "StringCollectionBinding")]
public sealed class TestStringCollectionBindingCommand : PSCmdlet
{
    [Parameter(Mandatory = true)]
    public StringCollection Value { get; set; }

    protected override void ProcessRecord()
    {
        WriteObject(Value[0]);
    }
}
'@

$type = Add-Type -TypeDefinition $source -PassThru
Import-Module -Assembly $type.Assembly

# Select-Object emits one scalar PSObject wrapping a string.
$value = 'test-value' | Select-Object -Unique

$value.GetType().FullName
$value -is [System.Management.Automation.PSObject]

Test-StringCollectionBinding -Value $value

# The control case succeeds:
Test-StringCollectionBinding -Value ([string[]]$value)

# Multiple pipeline results also succeed:
$values = 'first', 'second' | Select-Object -Unique
Test-StringCollectionBinding -Value $values
```

### Expected behavior

```console
System.String
True
test-value
```

### Actual behavior

```console
System.String
True

Test-StringCollectionBinding:
Cannot convert 'expected' to the type
'System.Collections.Specialized.StringCollection' required by parameter
'Value'. Unable to cast object of type
'System.Management.Automation.PSObject' to type 'System.String'.
```

### Error details

```console
Exception             : 
    Type              : System.Management.Automation.ParameterBindingException
    Message           : Cannot convert 'test-value' to the type 'System.Collections.Specialized.StringCollection' required by parameter 'Value'. Unable to cast object of type 'System.Management.Automation.PSObject' to type 'System.String'.
    ParameterName     : Value
    ParameterType     : [System.Collections.Specialized.StringCollection]
    TypeSpecified     : [System.Management.Automation.PSObject]
    ErrorId           : CannotConvertArgument
    Line              : 22
    Offset            : 37
    CommandInvocation : 
        MyCommand        : Test-StringCollectionBinding
        ScriptLineNumber : 22
        OffsetInLine     : 1
        HistoryId        : 1
        Line             : Test-StringCollectionBinding -Value $value 2>$null

        Statement        : Test-StringCollectionBinding -Value $value 2>$null
        PositionMessage  : At line:22 char:1
                           + Test-StringCollectionBinding -Value $value 2>$null
                           + ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        InvocationName   : Test-StringCollectionBinding
        PipelineLength   : 1
        PipelinePosition : 1
    ErrorRecord       : 
        Exception             : 
            Type    : System.Management.Automation.ParentContainsErrorRecordException
            Message : Cannot convert 'test-value' to the type 'System.Collections.Specialized.StringCollection' required by parameter 'Value'. Unable to cast object of type 'System.Management.Automation.PSObject' to type 'System.String'.
            HResult : -2146233087
        CategoryInfo          : InvalidArgument: (:) [Test-StringCollectionBinding], ParentContainsErrorRecordException
        FullyQualifiedErrorId : CannotConvertArgument,TestStringCollectionBindingCommand
        InvocationInfo        : 
            MyCommand        : Test-StringCollectionBinding
            ScriptLineNumber : 22
            OffsetInLine     : 37
            HistoryId        : 1
            Line             : Test-StringCollectionBinding -Value $value 2>$null

            Statement        : $value
            PositionMessage  : At line:22 char:37
                               + Test-StringCollectionBinding -Value $value 2>$null
                               +                                     ~~~~~~
            CommandOrigin    : Internal
        ScriptStackTrace      : at <ScriptBlock>, <No file>: line 22
    TargetSite        : 
        Name          : EncodeCollection
        DeclaringType : [System.Management.Automation.ParameterBinderBase]
        MemberType    : Method
        Module        : System.Management.Automation.dll
    Data              : 
        System.Management.Automation.Interpreter.InterpretedFrameInfo, System.Management.Automation, Version=7.6.0.500, Culture=neutral, PublicKeyToken=31bf3856ad364e35 : <ScriptBlock>

    InnerException    : 
        Type       : System.InvalidCastException
        TargetSite : 
            Name          : ChkCastAny_NoCacheLookup
            DeclaringType : [System.Runtime.CompilerServices.CastHelpers]
            MemberType    : Method
            Module        : System.Private.CoreLib.dll
        Message    : Unable to cast object of type 'System.Management.Automation.PSObject' to type 'System.String'.
        Source     : System.Private.CoreLib
        HResult    : -2147467262
        StackTrace : 
   at System.Collections.Specialized.StringCollection.System.Collections.IList.Add(Object value)
   at System.Management.Automation.ParameterBinderBase.EncodeCollection(CommandParameterInternal argument, String parameterName, ParameterCollectionTypeInformation collectionTypeInformation, Type toType, Object currentValue, Boolean 
coerceElementTypeIfNeeded, Boolean& coercionRequired)
    Source            : System.Management.Automation
    HResult           : -2146233087
    StackTrace        : 
   at System.Management.Automation.ParameterBinderBase.EncodeCollection(CommandParameterInternal argument, String parameterName, ParameterCollectionTypeInformation collectionTypeInformation, Type toType, Object currentValue, Boolean 
coerceElementTypeIfNeeded, Boolean& coercionRequired)
   at System.Management.Automation.ParameterBinderBase.CoerceTypeAsNeeded(CommandParameterInternal argument, String parameterName, Type toType, ParameterCollectionTypeInformation collectionTypeInfo, Object currentValue)
   at System.Management.Automation.ParameterBinderBase.BindParameter(CommandParameterInternal parameter, CompiledCommandParameter parameterMetadata, ParameterBindingFlags flags)
   at System.Management.Automation.CmdletParameterBinderController.BindParameter(CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
   at System.Management.Automation.CmdletParameterBinderController.BindParameter(UInt32 parameterSets, CommandParameterInternal argument, MergedCompiledCommandParameter parameter, ParameterBindingFlags flags)
   at System.Management.Automation.CmdletParameterBinderController.BindNamedParameter(UInt32 parameterSets, CommandParameterInternal argument, MergedCompiledCommandParameter parameter)
   at System.Management.Automation.ParameterBinderController.BindNamedParameters(UInt32 parameterSets, Collection`1 arguments)
   at System.Management.Automation.CmdletParameterBinderController.BindCommandLineParametersNoValidation(Collection`1 arguments)
   at System.Management.Automation.CmdletParameterBinderController.BindCommandLineParameters(Collection`1 arguments)
   at System.Management.Automation.CommandProcessor.BindCommandLineParameters()
   at System.Management.Automation.CommandProcessor.Prepare(IDictionary psDefaultParameterValues)
   at System.Management.Automation.CommandProcessorBase.DoPrepare(IDictionary psDefaultParameterValues)
   at System.Management.Automation.Internal.PipelineProcessor.Start(Boolean incomingStream)
   at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input)
--- End of stack trace from previous location ---
   at System.Management.Automation.Internal.PipelineProcessor.SynchronousExecuteEnumerate(Object input)
   at System.Management.Automation.PipelineOps.InvokePipeline(Object input, Boolean ignoreInput, CommandParameterInternal[][] pipeElements, CommandBaseAst[] pipeElementAsts, CommandRedirection[][] commandRedirections, FunctionContext 
funcContext)
   at System.Management.Automation.Interpreter.ActionCallInstruction`6.Run(InterpretedFrame frame)
   at System.Management.Automation.Interpreter.EnterTryCatchFinallyInstruction.Run(InterpretedFrame frame)
CategoryInfo          : InvalidArgument: (:) [Test-StringCollectionBinding], ParameterBindingException
FullyQualifiedErrorId : CannotConvertArgument,TestStringCollectionBindingCommand
InvocationInfo        : 
    MyCommand        : Test-StringCollectionBinding
    ScriptLineNumber : 22
    OffsetInLine     : 37
    HistoryId        : 1
    Line             : Test-StringCollectionBinding -Value $value 2>$null

    Statement        : $value
    PositionMessage  : At line:22 char:37
                       + Test-StringCollectionBinding -Value $value 2>$null
                       +                                     ~~~~~~
    CommandOrigin    : Internal
ScriptStackTrace      : at <ScriptBlock>, <No file>: line 22
```

### Environment data

```powershell
Name                           Value
----                           -----
PSVersion                      7.6.5
PSEdition                      Core
GitCommitId                    7.6.5
OS                             Microsoft Windows 10.0.26200
Platform                       Win32NT
PSRemotingProtocolVersion      2.4
SerializationVersion           1.1.0.1
WSManStackVersion              3.0
```

### Visuals

_No response_

Sunbelt Computer Software

PL/B Language Development and Support

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Uh oh!

Binary cmdlet binding fails to unwrap a scalar PSObject for StringCollection parameters #27969

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Sunbelt Computer Software

PL/B Language Development and Support

Uh oh!

Binary cmdlet binding fails to unwrap a scalar PSObject for StringCollection parameters #27969

Description

Prerequisites

Steps to reproduce

Expected behavior

Actual behavior

Error details

Environment data

Visuals

Activity

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

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