feat (bindings): expose beacon and beacon_info power levels on FFI

[Velin92]

This is required to allow a mod/admin to both check, and eventually change, the current power level value for the beacon and the beacon_info events.

[codecov]

Codecov Report

❌ Patch coverage is 93.10345% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 89.94%. Comparing base (2ec031b) to head (21bd307).
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/matrix-sdk/src/room/power_levels.rs	93.10%	0 Missing and 4 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6540      +/-   ##
==========================================
+ Coverage   89.92%   89.94%   +0.02%     
==========================================
  Files         381      381              
  Lines      105914   105972      +58     
  Branches   105914   105972      +58     
==========================================
+ Hits        95243    95317      +74     
+ Misses       7029     7010      -19     
- Partials     3642     3645       +3     

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[codspeed-hq]

Merging this PR will not alter performance

✅ 50 untouched benchmarks

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_{Comparing mauroromito/expose_beacon_and_beacon_info_pl (21bd307) with main (2ec031b)}