redundant face unlock header.
1. Change the FaceSettings theme style to avoid an action bar
appearing.
2. In AndroidManifest.xml to apply configChanges attribute for
handling device orientation.
Bug: 262497152
Test: manually to do reproduced steps:
Pre-Condition:
1. enroll face
2. enable auto rotate
Procedure:
1.go to settings > security > face & fingerprint unlock
2.enter screen lock
3.click face unlock
4.rotate device into landscape mode and then back to portrait mode
5.check the UI
Test: make RunSettingsRoboTests ROBOTEST_FILTER="com.android.settings
.biometrics.face.FaceSettingsActivityTest"
Change-Id: I4ee1bb4f061ea2d141043405213ba6e60bacd92f
2ca753bd06