Workaround for slow -1 drawing when swiping home

- Recents animation is the one most affected by this visually (other
  transitions are blocked from starting entirely, which is another
  issue).  TLDR, the -1 is always visible by modulates the alpha
  of its window as the user swipes to/from it.  As such, it's still
  considered an interesting window for allDrawn purposes, but in rare
  cases, AGSA may not be scheduled and the drawing of the -1 window
  even if it is alpha=0, will block Launcher's allDrawn state and
  prevent the Launcher surface from being shown.

  As a workaround, we ignore non-base windows associated with the
  recents animation target activity if their alpha is 0 for the purposes
  of considering when all windows are drawn.

Bug: 245407006
Test: TBD
Change-Id: I91ed411eb36e23f22c0a3b2bbbd80b6632b8c0b5