Send initial isFingerprintEnrolled when userChanges

So the state isn't stale on user switches.

Bug: 342970807
Flag: EXEMPT bugfix
Test: atest BiometricSettingsRepositoryTest
Test: - Enroll UDFPS on primary and secondary users.
 - On the secondary user, set security to NONE.
 - Switch to primary user.
 - Observe alternate bouncer will appears when tapping
 on a notification or longpressing QS tiles
Change-Id: I4f39debc5376ee8592c9a1ce3aa902d2dd702c40