Fixes #7391

When Redis rejects writes transiently (e.g. during replica resynchronization with NOREPLICAS, failover, or ACL updates):

1. Watchdog renewal was abandoned on failure: In renewExpiration(), if the renewal execution future failed with an error, it was never rescheduled. Once reliableTopicWatchdogTimeout elapsed, the subscriber score expired.
2. Post-poll status update script stopped the poll loop on error: If updateFuture failed, poll(id) was not rescheduled, permanently halting message consumption for active subscribers.
3. Large score formatting in Lua script: In Lua, large integers format in scientific notation with tostring(), causing Redis stream ID parsing errors (ERR Invalid stream ID specified as stream command argument) when consumer groups are destroyed.

This change:

• Reschedules renewExpiration() when renewal fails and subscribed.get() == true.
• Retries poll(id) with backoff when updateFuture encounters a transient failure while still subscribed.
• Guards empty consumer groups in the status update Lua script and uses string.format('%.0f', score).