Udfps icon, udfps bouncer, and lockicon/button bug fixes

- Delay updating visibility of the  LockIcon/Button when the FPS running
state changes to false. The fingeprint listening state may be cancelled on
screen off and immediately restarted on entering AOD. During this brief
moment, we don't want to flash the grey button (affordance for bouncer
when fps isn't running).

- Remove keyguard visibility check from UdfpsKeyguardViewController -
this was delaying showing the udfps icon on AOD since the visibilty
changes too late.

- Update udfps bouncer logic - only show the generic bouncer from
showBouncerIfKeyguard if we're on the keyguard and bouncer isn't about
to show (from swiping up from the bottom).

- Reset leaveOpenOnKeyguardHide when a user exits the bouncer from a
backpress. We don't want this state to linger into the next auth
attempt.

Test: manual
Fixes: 188605736
Fixes: 187131910
Fixes: 185951882
Change-Id: Ibcddccdde0173b312404ea33741adc6a15efab6b