Modernize UDFPS views for maintainability

Gated behind flag: REFACTOR_UDFPS_KEYGUARD_VIEWS

UdfpsKeyguardView is composed of the following views
which now all have their own ViewModels and ViewBinders:
  - udfps_keyguard_view_internal
      - aod_view
      - lockscreen_view
      - lockscreen_background_view

Additionally, this CL also adds an animation `toAlternateBouncer`
which animates the scale and color of UDFPS. See
UdfpsLockscreenViewModel.

This CL doesn't handle alpha changes based on bouncer,
shade, qs, dialog, and activity launches.

Test: atest UdfpsAodViewModelTest UdfpsFingerprintViewModelTest
Test: atest UdfpsLockscreenViewModelTest
Test: atest UdfpsKeyguardInteractorTest
Bug: 278719514
Change-Id: Id07499989585bb229afde8de17492bf1ef2a2776