Enable secondary_user_on_secondary_display for CtsUiRenderingTestCases

secondary_user_on_secondary_display is for background users that have
access to UI on assigned displays (a.k.a. visible background users) on
devices that have config_multiuserVisibleBackgroundUsers enabled. The
main use case is Automotive's multi-display Whole Cabin experience where
passengers (modeled as visible background users) can interact with the
display in front of them concurrently with the driver (modeled as the
current user) interacting with driver's display.

Bug: 373480710
Flag: TEST_ONLY
Test: atest CtsUiRenderingTestCases
Test: atest --user-type secondary_user_on_secondary_display \
        CtsUiRenderingTestCases
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:3cc83af718347342c744c34f0db6e8fc36ee7850)
Merged-In: Ia06b61a8029b003999dce287110cd87a6667b49d
Change-Id: Ia06b61a8029b003999dce287110cd87a6667b49d