plugins/overview: Bind values to 1:1 animation while gesture is ongoing

Otherwise the animation feels wrong while activating with a gesture.
Now when a 1:1 gesture is ongoing, then the Overview effect will stop
animating the overviewVal/gridVal values. I implemented this by porting
to states, giving 1:1 gestures their own states, and only animating the
change between states.

BUG: 476536