Ensure updateActiveUser is called before generateChallenge

generateChallenge may be invoked if the HAL crashes while the device
is on keyguard. Always schedule this for now. The updateActiveUser
client is already optimized to not invoke IBiometricsFace#setActiveUser
if we are already the target user.

Fixes: 172885666
Test: manual
Change-Id: I16f22ff3ffc18f031bc02c0cb37a3bc5fc591940