Reset Task surface to fullscreen when appeared

Some other modes leave the task surface in a bad state, so if
fullscreen gets onTaskAppeared, reset everything to fullscreen

Bug: 168278812
Test: Open an app, put it into pip, close pip by dragging to X,
      open the app from recents.
Change-Id: Icf4df30eb44fa0a589e7d0bd9be1eb2e72fc492a