Configure BiometricPrompt to use AuthService.

BioetricPrompt was incorrectly using BiometricService directly. After
adding a few minor modifications, BiometricPrompt correctly goes through
AuthService.

Test: Verified that BiometricPromptDemo apk is able to authenticate.
Test: Verified that BiometricPromptDemo apk is able to cancel
authenticatoins.
Bug: 141025588

Change-Id: I29646c33a1904c6ad71f3ed2a4b02b6fe159517b
3 files changed