[Dual Shade] Fade in the QS header content with the rest of status bar.

Fix: 414769166
Test: Manually tested by opening and closing the Quick Settings shade
 and observing the battery estimate text fade in/out correctly with the
 status bar.
Flag: com.android.systemui.scene_container
Change-Id: Ib7444b92767c7963ad4737b5c88a179695ba201a