Don't cache mIsUdfpsEnrolled

AuthController.isUdfpsEnrolled no longer makes
any IPC calls, so we don't need to cache the value
in KeyguardUpdateMonitor which can cause the state
to be stale.

Test: manually check dumpsys on reboot, udfps enrollment state
is correct
Test: atest SystemUITests
Fixes: 218718078
Change-Id: I4f81465743cdea9e8f01b6bfd5637d0ee450c29a