Let the SyncAPI know that we changed account data on room upgrade

[S7evinK]

This should help with matrix-org/complement#819

Pull Request Checklist

• I have added Go unit tests or Complement integration tests for this PR or I have justified why this PR doesn't need tests
• Pull request includes a sign off below or I have already signed off privately

[codecov-commenter]

Codecov Report

❌ Patch coverage is 22.72727% with 34 lines in your changes missing coverage. Please review.
✅ Project coverage is 52.26%. Comparing base (d9c63c8) to head (8e00556).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
userapi/consumers/roomserver.go	22.72%	28 Missing and 6 partials ⚠️

❌ Your patch status has failed because the patch coverage (22.72%) is below the target coverage (75.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3668      +/-   ##
==========================================
+ Coverage   52.21%   52.26%   +0.05%     
==========================================
  Files         524      524              
  Lines       48376    48399      +23     
==========================================
+ Hits        25258    25298      +40     
+ Misses      19604    19592      -12     
+ Partials     3514     3509       -5     

Flag	Coverage Δ
unittests	52.26% <22.72%> (+0.05%)	⬆️

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[devonh]

Thanks for taking this on so quickly after the complement test was written 😄