Remove multi-biometric interstitial screen in SUW

On devices with multiple biometric sensors, this removes the
interstitial screen in Setup Wizard that let the user choose whether to
enroll face, fingerprint, or both. Instead, such devices will always
show face enrollment followed by fingerprint, with the option to skip
either or both.

Test: Manually tested all enroll/skip combinations in SUW

Fixes: 183720580
Change-Id: I7f045579f732196bde28dd96e9443e4bb4c906ae