Reset isFoldHandled

isFoldHandled was never getting reset to true. This caused a potential
race condition when:

1. AOD enabled
2. Unfold the device
3. Fold the device.
4. Cover prox sensor to turn display off, such as a person would when
putting the phone in purse or pocket
5. Take phone out and immediately unlock with SideFPS

This was causing onScreenOn to run, and FoldAodAnimationController to
rerun `showAodUI` incorrectly. If the timing was just right, this
would force the device into KEYGUARD state after being unlocked.

Fixes: 273681779
Test: manual, need to do the steps above
Test: atest FoldAodAnimationControllerTest
Change-Id: I09dc417d03763ede4d2bea1c7d51183503170a40