Add aconfig flag for contextual tips about power off, take screenshot.

Bug: 322891421
Change-Id: Ie3fb2de4ed667f6062a91500aef1c2875ac51065
Test: NONE this just adds the flags. No change in behavior.
Flag: ACONFIG com.android.systemui.enable_contextual_tip_for_power_off DEVELOPMENT
1 file changed