Modernize alternate bouncer logic

Test: atest BiometricRepositoryTest
Test: atest UdfpsKeyguardViewControllerWithCoroutinesTest
Test: atest AlternateBouncerInteractorTest
Test: atest SystemUITests SystemUIGoogleTests
Test: install DPM test app, change device policy requirements
and see that biometric repository is correctly updated
Bug: 237362467

Change-Id: Ia975fd65d929505d7e1259cfca1dede4cfbc8704