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: I95249d8f24093d65c8251576dc3c145ba5b4ff50