AOD: Block when fingerprint is already authenticated but waiting for goingToSleep to complete

Improves an issue where immediately triggering fingerprint after
the devices goes to sleep results in a lot of flickering.

There's still flicker however if the fingerprint authenticates after we've requested the AOD
display state, but before it has actually been applied.

Bug: 62887179
Test: Go to Home. Lock screen. Immediately unlock via fingerprint. Verify that the AOD screen does not even show.
Change-Id: Ib6425eee803a8c7e02f9621a571e562e825af57f