Modified Fp -> Face setup flow

Test: Skip FP, Enroll Face, hit back button, observe that you will go
back to Fingerprint enrollment.
Test: Verify that after completing a biometric enroll we no longer
show the introduction activity with a "Done" button.
Fixes: 229813512

Change-Id: Ie0d7ce5d5cef084b3614afce10e05dc72c86b492