Cover the remaining interfaces of libraries/troubleshoot, libraries/matrixmedia,
libraries/dateformatter, libraries/featureflag, libraries/workmanager and
libraries/mediaviewer, along with their members and parameters.
Behaviours worth recording: NotificationTroubleshootTest reports its outcome
through its state flow rather than by returning, and its quickFix throws unless
the test offers one; DateFormatter.format turns a null timestamp into an empty
string so callers need no null check; ImageLoaderHolder keeps one loader per
session because decrypting room media needs that session's client.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Benoit Marty