1. Change to FooterBarMixin
2. Move FooterButton to the same package with FooterBarMixin
Bug: 120805516
Test: RunSettingsRoboTests
Change-Id: Ic6937e3cbc515dd7bf877c9193932cd5800ac801
FotterButton constructor in setupcompat will be deprecated, change to
use builder.
Bug: 120805516
Test: RunSettingsRoboTests
Change-Id: Ic84b0c91205bf3c770bc658e8eaf2626e4d7bddd
Bug: 110589286
Test: fingerprint enrolling still works
Test: enrollment flow with and without a pin set up still works properly
Test: enrollment continues when configuration changes, stops otherwise
Change-Id: I39f76c7f1a16e9533cef573f87cf4b81cb20cb18