[native] have saving thread avatar loaders only appear for thread being updated

Summary:
Added the activeThreadID/threadID to the thread settings loading status selector custom keys. This fixes the issue where if we update a thread avatar the loaders would be shared and shown across different threads.

Depends on D7629

Test Plan:
Tested that the loader only appeared in the thread avatar I was updating:

Reviewers: atul, ashoat

Reviewed By: ashoat

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D7679