ClearBiometricRecognized when user switches

User unlock states should be cleared whenever user switches. Otherwise,
it's possible for the following sequence of events

1) Unlock first user via biometrics
2) Do not dismiss keyguard, switch to second user
3) Switch back to first user - can unlock without authenticating

Fixes: 151906507

Test: Repeat steps above, does not occur anymore
Test: atest KeyguardUpdateMonitorTest
Change-Id: I1d8e5867a18a680e85be8c335f09d4cb4209612e