[native] change type for useProcessSelectedMedia from MediaLibrarySelection to NativeMediaSelection
Summary: we need to do this so we can extend useProcessSelectedMedia to handle images from camera capture in addition to images from photo gallery selection
Test Plan: flow
Reviewers: atul, ashoat
Reviewed By: ashoat
Subscribers: ashoat, tomek, atul
Differential Revision: https://phab.comm.dev/D7548