Update Face Unlock strings to the latest versions

Makes the following changes to strings related to Face Unlock:
- Standardize capitalization of "Face Unlock"
- Use latest versions of traffic light face enroll strings
- Use latest versions of combined biometrics settings strings
- Set SUW description strings programmatically instead of in XML

Test: Manually tested Face Unlock traffic light and grid UIs

Bug: 183649070
Change-Id: Ie67978ae2630493a5b03b00c3f8a639066ab8f3a