Transform closing window to icon on workspace using adaptive icons.

With adaptive icons, we can have FloatingIconView match the shape
and size of the closing window, regardless of the icon shape.

FloatingIconView starts off as a rounded rect (same corners as task view)
and then morphs into the icon shape using FolderShape#createRevealAnimator
in reverse.

Decided to add FeatureFlag.ADAPTIVE_ICON_WINDOW_ANIM since there are still
some issues with folders, badges, and a visible jump when swapping the
FloatingIconView with the original icon.

Bug: 123900446

Change-Id: I94969eea6d5f4b932a84a11eb403611276042b46