Made permission dialogs non-dismissible

This implementation is the solution discussed in b/301901026. This change keep the permission grant dialog open when tapped outside of the grant window, making the dialog non-dismissible.

Bug: 301901026
Test: Open camera for the first time, tap outside of the grant request dialog. The dialogs does not dismiss/close anymore.
Change-Id: I71422890eb472d6ca49e8a921a6be87b28171bbd