Make entire screen touchable if screen off is playing.

Previously we relied upon the panel expansion state to
consume these touches, but something changed with how
that is dispatches, and it now comes in later in the
screen off animation.

This way, we explicitly consume all touches whenever
the animation is playing, and recalculate whether or
not we do that whenever we sleep/wake.

Fixes: 224592908
Test: tap launcher icons right after pressing power
Change-Id: I075c8028e52d6103127c05b60f341fd64ef07634