Reset messages when the keyguard isn't showing

- biometric error messages require a minimum amount of time
to be shown but aren't relevant once the device is unlocked,
so clear the keyguard indication messages once the keyguard
isn't showing anymore
- don't show any face errors for co-ex

Test: manual, atest SystemUITests
Fixes: 192981147
Change-Id: Ia11ffc740e5505aafb7f96635909bf7f5cd10341