test(threads): add tests for checking the push rule behavior with respect to threads subscriptions

[bnjbvr]

This adds a large integration test, that will exhaustively check all our notification modes, and how they relate to thread subscriptions:

• for each interesting global notification behavior (all messages / mentions only),
• for each interesting room notification behavior (all messages / mentions only / mute),

Look if a subscribed thread will trigger a mention or not.

There are a few false-negatives, which motivated matrix-org/matrix-spec-proposals@bd9e842 in the spec. This PR will make it possible to check that these cases have been fixed, after implementing the new behavior from that spec update.

Part of #5038.

[codspeed-hq]

CodSpeed Performance Report

Merging #5565 will not alter performance

_{Comparing bnjbvr/push-rules-exhaustive-testing (8b38d59) with main (25a8187)}

Summary

✅ 37 untouched benchmarks

[codecov]

Codecov Report

❌ Patch coverage is 95.16129% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.65%. Comparing base (25a8187) to head (8b38d59).
⚠️ Report is 18 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/matrix-sdk/src/room/mod.rs	86.66%	2 Missing ⚠️
crates/matrix-sdk/src/test_utils/mocks/mod.rs	97.72%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #5565   +/-   ##
=======================================
  Coverage   88.64%   88.65%           
=======================================
  Files         340      340           
  Lines       95065    95127   +62     
  Branches    95065    95127   +62     
=======================================
+ Hits        84273    84331   +58     
- Misses       6607     6610    +3     
- Partials     4185     4186    +1     

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[stefanceriu]

Very nice, lgtm 👍