Fix the global gesture to enable accessibility.

1. There was a bug in the touch explorer which was crashing almost
   every time after accessibility was enabled via the gesture. The
   problem was that in dragging state when a finger goes up we were
   not transitioning to touch exploring state.

2. The global actions dialog was not going away after enabling
   accessibility while it should as the user brought it up to
   turn accessibility on rather to interact with global actions.

bug:15254250

Change-Id: Iaa45f758e09566822775b53e87d2980138e85ef9