Update light reveal + udfps icon vis

When AOD is enabled/disabled, update visibility of the LightRevealScrim.

When device is animating the screen off animation from Home => Keyguard,
don't show the udfps icon. (Note, we still want to show the udfps icon
on transitioning between LS <=> AOD).

Move UdfpsKeyguard pauseAuth logic into UdfpsKeyguardViewController
instead of abstract class UdfpsViewController.

Test: manual
Test: atest UdfpsKeyguardViewControllerTest
Fixes: 182914128
Fixes: 184373073
Change-Id: Ic831e462d49a603bf214453e25b5bcbd925c5c3d