Update biometricUnlockMode with biometricUnlockSource

These were previously updated separately and the timing
of checking one or the other couldn't be guaranteed. Consolidate
these two values that should only be updated together into
the BiometricUnlockState.

Fixes: 330739233
Bug: 319035806
Flag: None
Test: atest DeviceEntrySourceInteractorTest
Change-Id: I90ab1bc48ce473dd6145065fb3668b7b7581a12f