Add a templated customized view API on Biometric Prompt.

go/custom-bp

Test: atest BiometricPromptRequestTest
Test: atest PromptViewModelTest
Test: manual test - add content view manullay and test on biometric test app
Flag: ACONFIG android.hardware.biometrics.custom_biometric_prompt DEVELOPMENT
Bug: 302735104
API-Coverage-Bug: 302735104

Change-Id: I3a55a71790089c774e838106626e015f3426420b