Fix double divider in Privacy page

The second divider is shown after we set a background to the pinned
header.

- Simply hide the pinned header instead of its inner views.
- Move setActionBarShadowAnimation to controller and just call it when
  the bar chart is available.

Fixes: 134652710
Test: robotest, visual
Change-Id: I4381e5ca1a042583d3e5874f5600719267b19786