Set unlockAmount = 1f when keyguardGoingAway = false.

This is a fail-safe to fix the ongoing tiny launcher issue that
has been reported but with no reliable repro steps. My best guess
is that this involves occluding activities that also dismiss an
already-unlocked keyguard (such as one unlocked by face auth),
such that we prepare to unlock to Launcher but then never start
the animation since we are already unlocked + Launcher is no
longer underneath.

I am able to force reproduce this by modifying
canPerformInWindowAnimations to always return true, and then
launching an occluding activity.

This should be a safe fix as it only applies the unlockAmount = 1f
if we think the keyguard is no longer going away and we've left the
Launcher at unlockAmount < 1f. At the very least, the worst possible
regression should be that we set unlockAmount = 1f at an inopportune
time, cancelling the unlock animation but leaving the device in a
good state.

Fixes: 240906324
Test: always return true from canPerformInWindowAnimations and unlock
Change-Id: Id9c0e6c66cd4995b817e7a145576c5424b6561e0