Revert "Revert "Copy startup & callback mechanism from fingerprint to face service.""

This reverts commit 8f5bb9d3 with a fix for change to the singleProvider method caused some tests on virtual devices to fail.

Refactors some fingerprint-only logic into a shared module so the face service can apply the same start & callback model. This will enable some keyguard optimizations for face auth that were previously made for fingerprint.

Bug: 221037350
Test: atest KeyguardUpdateMonitorTest AuthControllerTest DozeSensorsTest LockIconViewControllerTest FaceServiceRegistryTest FingerprintServiceRegistryTest BiometricStateCallbackTest
Test: manual (via BP test app)

Change-Id: I365c11858d8fbba74fad350932f3c7ae25c297fd