Revert "Make new headers flag true by default"

Revert submission 20248350-flipFlag

Reason for revert: Part of DM+Platinum rotation as a culprit for b/255588071. 

Reverted Changes:
I51a3b403f:Fix touches in Large screen header
I01da41161:Use split_shade_header in all configurations
Ie0019d212:Make new headers flag true by default

Change-Id: I119bea7e033f28db0539b0aff4a1d02087ee55af