Use custom drawable for UDFPS enrollment progress bar

1) Removes UdfpsProgressBar and associated baggage
2) Creates entirely custom UdfpsEnrollProgressBarDrawable to support
   any required UX going forwards
3) UdfpsEnrollProgressBarDrawable is owned by UdfpsEnrollDrawable.
   UdfpsEnrollDrawable should be the source of truth for any
   UDFPS enrollment animations.

Note: This moves the handler up a few layers to UdfpsEnrollView, so
that child views/drawables receive callbacks on the right thread.

Bug: 187460696
Test: manual

Change-Id: If3362e340de8074e62cb5f69e739c1d687914fad