Add mumd support to settings tests

Update tests to use apis targetting the user being run. Migrated away
from UiScrollables which defaulted to the default display and instead
used UiObject2 which can more easily be used on specific displays.

Bug: 339049586
Test: atest CtsSettingsTestCases && atest --user-type secondary_user_on_secondary_display CtsSettingsTestCases
Change-Id: Ide194f89fde992141b4306b879bb9ba74f959745