Sliding Sync: Ensure changes to the requested required_state trigger a sync response

[MadLittleMods]

Ensure changes to the requested required_state trigger a Sliding Sync response

Fix #18844

Dev notes

Alternative: Immediately notify Sliding Sync for required_state changes

compute_interested_rooms(...)

_required_state_changes(...)

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.rest.client.sliding_sync

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.rest.client.sliding_sync.test_rooms_required_state.SlidingSyncRoomsRequiredStateTestCase_new.test_rooms_required_state_expand_retract_expand

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.rest.client.sliding_sync.test_rooms_required_state.SlidingSyncRoomsRequiredStateTestCase_new.test_rooms_required_state_expand_retract_expand_without_new_activity

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.rest.client.sliding_sync.test_rooms_required_state.SlidingSyncRoomsRequiredStateTestCase_new.test_rooms_required_state_expand_with_same_pos

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.handlers.test_sliding_sync

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.handlers.test_sliding_sync.ComputeInterestedRoomsTestCase_new

SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial tests.handlers.test_sliding_sync.RequiredStateChangesTestCase

Todo

• Update compute_interested_rooms(...) to take into account changes to the requested required_state
• When people are using a timeout should we immediately respond if we see the requested required_state change. The answer is probably but this may be tricky. Currently, we will just notifier.wait_for_events(...) until some new activity occurs.

Pull Request Checklist

• Pull request is based on the develop branch
• Pull request includes a changelog file. The entry should:
  • Be a short description of your change which makes sense to users. "Fixed a bug that prevented receiving messages from other servers." instead of "Moved X method from EventStore to EventWorkerStore.".
  • Use markdown where necessary, mostly for code blocks.
  • End with either a period (.) or an exclamation mark (!).
  • Start with a capital letter.
  • Feel free to credit yourself, by adding a sentence "Contributed by @github_username." or "Contributed by [Your Name]." to the end of the entry.
• Code style is correct (run the linters)