1. Set thread emoji avatar
2. Make sure it's set correctly
3. Set image avatar
4. Make sure it's set correctly
5. Send a bunch of identical "set image avatar" requests
6. Make sure `updateThread` endpoint is idempotent
7. Clear image avatar
8. Make sure thread avatar is cleared
9. etc etc
Basically set/unset thread avatar multiple times to make sure DB/client were as expected. Also tested various non-avatar thread changes to make sure that there are no regressions.
Here's a demo of setting/unsetting image thread avatar: