[native] Fix cropped avatar selection

Summary:
Fixes cropping part of ENG-4053.

Avoided replacing image URI with fetched asset URI when the file is in app's cache dir - this is where expo-image-picker stores cropped images.

Test Plan: Set cropped photo as an avatar - it is set correctly. Sent multimedia both with media gallery and image picker - both ways work. Checked both iOS and Android.

Reviewers: atul, ashoat, ginsu

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D8739