[native] Add alert when exiting edit mode by clicking the exit button
Summary: We want to make sure, that the user wanted to close the editing panel. Created a discard edited changes modal. It displays only if there are some changes in the message.
Test Plan:
Run the app on iOS.
- Selected message to edit. Edited it. Pressed exit edit mode button. The alert appears.
- Checked if the alert only appears if there are some changes in the message.
- Checked if in both scenarios we restore the message draft after exiting edit mode.
Reviewers: michal, inka, ginsu
Reviewed By: inka
Subscribers: ashoat, tomek, atul
Differential Revision: https://phab.comm.dev/D7349