[native] Launch message editing on mobile
Summary: Doing this via feature flag service carries the risk that the request times out. Until that problem is solved, figure it's safer to launch via code change.
Test Plan: Message editing has been tested by @kuba already. For this simple change, relying on Flow / ESLint
Reviewers: kuba, atul
Reviewed By: atul
Subscribers: tomek, kuba
Differential Revision: https://phab.comm.dev/D8005