Don't show hint while authenticating, show hint while pending confirmation

Also, restore "enabled" state of confirm button, otherwise it becomes
available when changing configurations.

Also, "confirm" button should become visible+disabled when tapping try again

Fixes: 135618797

Test: E2E fingerprint and face, with various tests such as rotation during
      various states

Change-Id: I1073a4479077355f1c275faed933ac8510927251