Fix animation video render issue when Settings->Moves is resumed from

screen off.

Re-initialize the animation video if necessary when the preference is
visible to the user.

Fixes: 31023261

Test: manual -
1. Go to Settings -> Moves and verify that the animation video are
displayed correctly on load.
2. Press power button to turn screen off, then on again. Verify when
Moves settings resumes, the animation video is displayed correctly.
3. Repeat #2 above but let display time out instead of turning off
screen by power button.

Change-Id: I0ee21d23a4c402b3a8463dca3b36fce67d651993
(cherry picked from commit 008ba4ec)