Don't also skip fingerprint in SUW when skipping face

Ensures that each biometric enroll intro activity handles an activity
result of RESULT_SKIP by calling the appropriate skip handler, rather
than just finishing. This fixes an issue where skipping face setup from
some Setup Wizard states would skip fingerprint setup as well.

Test: Manually skipped face setup from each screen during SUW

Bug: 193367620
Change-Id: If9ef9f19f8e967093f17dde98093a506400d7c09