Quickly fade in QSB when swiping up when SWIPE_HOME = false

Now that the "hook" gesture is supported for old quickstep to switch
apps, we need to fade out the QSB so it doesn't overlap the TaskView we
are switching to.

Bug: 111926330
Change-Id: Ie04c7909f6b96d12c810b438db89eedf8ea5bdeb
3 files changed