crypto: Notify when the identity status of a user changes

[andybalaam]

Part of element-hq/element-meta#2526

If you follow the stream returned from matrix_sdk::room::Room::subscribe_to_identity_status_changes you will receive an update every time someone in the room changes identity status e.g. becomes "Unpinned", meaning the UI should display a warning.

[codecov]

Codecov Report

Attention: Patch coverage is 94.96403% with 7 lines in your changes missing coverage. Please review.

Project coverage is 84.65%. Comparing base (c9fd5a0) to head (7ebc727).
Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
...x-sdk-crypto/src/identities/room_identity_state.rs	90.27%	7 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4022      +/-   ##
==========================================
+ Coverage   84.57%   84.65%   +0.08%     
==========================================
  Files         267      269       +2     
  Lines       28456    28600     +144     
==========================================
+ Hits        24066    24211     +145     
+ Misses       4390     4389       -1     

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[andybalaam]

@richvdh not sure what you force-pushed yesterday, but it appeared to delete identity_status_changes.rs so I added it back in a778d5c

[richvdh]

@richvdh not sure what you force-pushed yesterday, but it appeared to delete identity_status_changes.rs so I added it back in a778d5c

argh sorry, yes. Failure to git add after a git reset

[BillCarsonFr]

Some questions/comments

[BillCarsonFr]

Approved