Suppress the action bar in SetupChooseLockGeneric

The collapsing toolbar is introduced on S, which caused the Choose a
screen lock page has two different header. This CL is to supress the
collapsing toolbar from this page and also apply color extraction to the
page.

Bug: 190499041
Test: manual test
Make sure there's no collapsing toolbar in the page.

Change-Id: I8b7ea089bd9e9e7acdf0236099b1eb6270f0a816