Add test flags for battery tips.

When this flag is true, we will show related battery tip by force.
Then we can manually test and verify the UI behavior.

Following CL will add test flag for "app restriction" since it is
a little tricky.

Bug: 77477035
Test: RunSettingsRoboTests

Change-Id: Ib12ff4aa8bcc998ea6a73f461c3d5f7fcc39b019