If enrolled show udfps bouncer on camera roll auth

- Add PowerManager.userActivity when user uses udfps to authenticate
so the screen won't turn off prematurely
- When the udfps-bouncer is showing, tapping outside the udfps view will
show the regular pin/pattern/password bouncer

Fixes: 184927116
Fixes: 182500156
Test: atest SystemUITests
Test: manual
  1. enroll udfps
  2. go to locked lock screen
  3. double tap power button to bring up camera
  4. tap on camera gallery (lock icon on image, bottom right)
  Observe: udfps is highlighted; tapping outside udfps area brings up
  regular bouncer

Change-Id: If01ee16647499fc2cf73afe527053cd6830a50ed