Establish CASE on re-subscription

[woody-apple]

This adds support for re-establishing CASE on re-subscription if a CHIP_ERROR_TIMEOUT was encountered as a default policy implementation, with the application having the ability to over-ride that if needed.

Fixes #16202

This works out-of-the-box if you call SendAutoResubscribeRequest.

This deletes the function-callback approach in ReadPrepareParams::mResubscribePolicy and uses instead the re-named, ReadClient::Callback::OnResubscriptionNeeded callback to effect the right re-subscription policy.

That callback now pivots from being just an informational callback to one that places the onus on the application (if it over-rides the default impl) to schedule the ensuing re-subscription by calling back into ReadClient::ScheduleResubscription.

Helper methods are provided to help applications pick and select elements of the default re-sub implementation as they desire.

Other notables:

• Fixes missing clean-up of timers on ReadClient destruction initiated by the application.
• Fixes missing error-handling of calls made during re-subscription to ensure they trigger further re-subscription.

Testing

1. Added a new TestSubscribeAttributeTimeout in TestRead.cpp that validates re-subscription sans CASE.
2. Added a new TestResubscription in the Python test suite that validates re-subscription with CASE.