[native] introduce EditAvatar component

Summary:
EditAvatar is a component that handles all the common logic between editing a user and thread avatar. Following diffs will handle the introduction of the logic for things like the action sheet, image picker, camera modal, loading, etc. in this component

Depends on D7324

Test Plan:
I am able to navigate to EmojiAvatarCreation using this new component from both the thread settings and profile. Please watch the demo video to see the changes I made

Reviewers: atul, ashoat

Reviewed By: ashoat

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D7438