Fix UDFPS unlock while waking with occlusion

UDFPS unlock while sleeping enters mode WAKE_AND_UNLOCK_PULSING, which
depends on delayed callback to hide the UDFPS overlay. This was being
canceled by a call to cancelAnimation from hideKeyguardImpl(), which
can be triggered multiple times. I can't find any harm in remove this
call to cancel.

Bug: 223088536
Test: Follow steps in bug
Change-Id: Id243c9a89bc3e281562169cf3c727d72fcfe10af