15e1d3f7e7
1) Make the resulting face/fingerprint can be @Nullable. Not all
removal callers care about the template that was removed, just
that they were all removed.
2) FingerprintService/FaceService should wait for all providers to
finish removing before notifying the upper layer of completion
Fixes: 183758063
Test: atest CtsBiometricsTestCases, notice
testLockoutResetRequestedAfterCredentialUnlock finishes
10 seconds quicker now (latch in LSS doesn't time out anymore)
Change-Id: I87c50ccf5524fd5440c9a6c2c7a0fd4cc61e684d