Add edu text to TV PiP

The edu text is added to the bottom of the TvPipMenuView, below the
pip content. This also makes the front and back pip menu surfaces
change size while the edu text is showing. It is shown for 10 seconds
and after that it is hidden by sliding upwards. This repositions the
PiP window so that it is placed properly (centered in case of expanded
pip).

This change introduces temporary decor insets - this is for the edu
text. Temporary decor insets don't interfere with the keep-clear area
algorithm - they will not cause the pip to move if they intersect with
a keep-clear area. They are only taken into account when calculating
the anchor bounds. Permanent decor insets are also taken into account
when calculating intersecting keep-clear areas

Bug: 219884907
Test: manual - start pip and check that the edu text is displayed and
      goes away after 10 seconds
Change-Id: Ie27c633c517903a4bf0b1544626bd00b621c19d4