Draw BubbleTextView drawable behind ClipIconView during app close animation.

The BubbleTextView drawable has built in shadows.

Prior to this, we waited for the FloatingIconView to finish
animating into place before fading in the BubbleTextView behind it.
We did this to prevent the shadow from blinking in.

Now that we've refactored FloatingIconView & ClipIconView,
we draw the BubbleTextView behind the ClipIconView so that the shadow is
revealed when the icon finishes clipping to its final shape and it
no longer has to be faded in.

Bug: 168608912
Change-Id: Ic0809f74ecbbec2f6e7caf7eca2fb560a8a02dec