Cancel existing launcher animation earlier to prevent unnecessary AllApps animation.

Prior to this change:
* User presses home before opening app transition finishes
* Close app transition starts
* AllAppsTransitionController#mProgress = 1.3 (starts offscreen)
* Launcher#onNewIntent makes call to AllAppsTransitionController#setStateWithAnimation
* targetProgress != mProgress (1 != 1.3),  so it runs an animator that looks odd
  ie. fast duration, only AllApps animates compared to expected full closing app transition

Change-Id: I755787aebf637675cb9aae23fc5784f5a5b6c811