Make the header INVISIBLE when alpha is 0

That way, clicks are not relayed to children.

Also, make the Reset menu item surface as action if it fits, for better
discoverability.

Test: manual
Test: atest LargeScreenShadeHeaderControllerTest
Fixes: 255708561
Change-Id: I853736f48ea97560f4b9ff438832d1372e0c59cc
4 files changed