Unifying swipe handling for fallback launcher

Previosuly we had a different swipe handler for 3P Launcher which
started either recents or Launcher based on the initial interaction
(horizontal or vertical). This was primarily because we had to wait
for recents transition to finish before starting another activity
which could delay going to home.

Now we always start recents transition to recentsActivity. This allows
us to use the same swipe handling logic as QuickstepLauncher. Home
activity can be started while recents transition is running and can be
controlled using onTaskAppeared callback.

Bug: 156924169
Bug: 156398988
Bug: 156295255
Change-Id: Ib9f02e0281e8d674bde2f4a81eca5fc8a5962144