[native] Blocking navigation in edit mode in the TabRouter

Summary: When we are in edit mode and the user made changes, we prevent him in this diff from changing tabs.

Test Plan:
On iOS:

• Navigate between threads - check if everything works.
• Navigate between tabs - check if everything works.
• Enter edit mode and make changes to the message,
• Change tab - should confirm with alert.

• Do the same in the sidebar (enter edit mode and check if the alert displays).

Reviewers: michal, inka, ashoat, tomek

Reviewed By: ashoat

Differential Revision: https://phab.comm.dev/D8304