[native] Introduce useNativeSetThreadAvatar and use throughout native

Summary:
Thread equivalent of D8341

setThreadAvatar previously had a call to displayFailureAlert, however, this function is only relevant on native since we don't display alerts on web.

As part of making the provider platform-agnostic, we "lift up" error handling/alert displaying to avatar-hooks.

We replace usages of setThreadAvatar on native with nativeSetUserAvatar.

Test Plan: The modified flows on native continue to work as expected.

Reviewers: ashoat, ginsu

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8757