What does this PR do?

Fixes function and webhook subscriptions to row/document upsert events, which were rejected with 400 general_argument_invalid ("Event is not valid").

For a 7-part pattern such as tablesdb.*.tables.*.rows.*.upsert, Event::isValid() reads the action from $parts[6] but looked it up one level too high, in $events[$type][$subType] (the tables / collections level). create, update and delete passed only because that level has actions with the same names. upsert exists only under rows / documents, so every row or document upsert subscription was refused.

The validator now checks the action against $events[$type][$subType][$subSubType] when the pattern has a sub-sub resource. 3-part and 5-part patterns are unchanged.

Test Plan

• Added unit assertions in tests/unit/Event/Validator/EventValidatorTest.php:
  • valid: tablesdb.*.tables.*.rows.*.upsert, tablesdb.books.tables.chapters.rows.*.upsert, databases.*.collections.*.documents.*.upsert, databases.books.tables.chapters.rows.prolog.upsert, documentsdb.*.collections.*.documents.*.upsert, vectorsdb.*.collections.*.documents.*.upsert
  • invalid: tablesdb.*.tables.*.upsert (upsert is not a table action), tablesdb.*.tables.*.rows.*.unknown
• Without the fix the test fails at the first upsert assertion. With the fix:
  • vendor/bin/phpunit tests/unit/Event passes (46 tests, 413 assertions)
  • pint --test passes on both files
  • phpstan analyse src/Appwrite/Event/Validator/Event.php reports no errors

Related PRs and Issues

• Fixes 🐛 Bug Report: Function and webhook events reject tablesdb.*.tables.*.rows.*.upsert ("Event is not valid") #14653
• Related: fix: add missing upsert event #10317 (added upsert to the events config)

Checklist

• Have you read the Contributing Guidelines on issues?
• If the PR includes a change to an API's metadata (desc, label, params, etc.), does it also include updated API specs and example docs? (No API metadata changes.)