[lib][native] Remove displayFailureAlert prop from EditThreadAvatarProvider

Summary:
As of D8757 we no longer need or use this prop. Surfacing of errors is handled by platform-specific code for consistency.

This is the thread avatar equivalent of D8342

Depends on D8757

Test Plan: NA/flow/eslint

Reviewers: ashoat, ginsu

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8758