[web] Added FocusTrap for modals

Summary:
Previously:
[web] Disabling tab when in edit mode
We want to prevent the user from using the tab when he is editing the message. Otherwise, he could navigate to other threads in the background.

We want to prevent users from focusing outside the modals. Added focus-trap-react library, to do that, and covered the modals that we use.

Test Plan: Checked if in edit mode and in other modals user can't focus outside the modal using the tab.

Reviewers: michal, inka

Reviewed By: michal

Subscribers: ashoat, tomek, atul

Differential Revision: https://phab.comm.dev/D7837