Adding a pending invisibility flag, which is used to indicate that the launcher

is not really invisible, but consider it invisible for window transitions

When a recents animation is cancelled, the callback can be received before or after the
wallpaper animation. To ensure that wallpaper animaiton runs properly, we keep the launcher
forceInvisible=true, only for that particular animaiton and false everywhere

Bug: 109735443
Change-Id: I5b22cc3327c8cd53a836d10e09fc88ae103becfc