feat(ffi): add bindings for listening to global send queue updates

[Johennes]

This is a small addendum to #5761 that does the same thing for the global update reporter.

CC @bnjbvr as the resident send queue expert.

• Public API changes documented in changelogs (optional)

[codecov]

Codecov Report

❌ Patch coverage is 0% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.42%. Comparing base (a11daf2) to head (66fc697).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/matrix-sdk/src/send_queue/mod.rs	0.00%	18 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5784      +/-   ##
==========================================
- Coverage   88.44%   88.42%   -0.03%     
==========================================
  Files         360      360              
  Lines       99879    99897      +18     
  Branches    99879    99897      +18     
==========================================
- Hits        88338    88331       -7     
- Misses       7397     7422      +25     
  Partials     4144     4144              

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[codspeed-hq]

CodSpeed Performance Report

Merging #5784 will not alter performance

_{Comparing Johennes:johannes/global-send-queue-update-bindings (66fc697) with main (e8fb133)}

Summary

✅ 50 untouched