Added different flow for re-enrollment

In order to enable this new flow, a user must currently have an enrolled
face and the security setting face_unlock_re_enroll must be non-zero.

Ex.
1. Enroll Face.
2. adb shell settings put
(secure face_unlock_re_enroll|secure_face_unlock_must_re_enroll) 1
3. If settings is opened, close it.
4. Open settings
5. Verify the new flow appears.

Bug: 141380252
Bug: 141254937
Test: Verified that the user's face is deleted after clicking delete.
Test: Verified that the user can re-enroll after removing their face.
Change-Id: I2b36a0bda5cb10fb33dfb2a5627d8fa40f14fb7e