9/n: Add BiometricScheduler proto dump

1) Adds biometrics.proto definition for BaseClientMonitor subtypes
2) Adds BiometricScheduler proto dump

When dumping the scheduler, the caller may request for the recent
operation queue to be cleared after dumping or not.

Note that we don't need BiometricScheduler.Operation#STATE_*
in the dump, since (for now) we just want to know what operations
have been run.

We can always add additional state, success/failure, etc in the
future if needed.

Bug: 159667191
Test: atest com.android.server.biometrics
Test: atest CtsBiometricsTestCases
Change-Id: I7d2350f00aaeef03ab7d74013b476af053240320