Enable secondary_user_on_secondary_display for CtsCompanionDeviceManagerMultiProcessTestCases

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: 364635408
Flag: TEST_ONLY
Test: atest CtsCompanionDeviceManagerMultiProcessTestCases
Test: atest --user-type secondary_user_on_secondary_display \
        CtsCompanionDeviceManagerMultiProcessTestCases
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:38a0626b4751949f32d86198aa25a47061f97feb)
Merged-In: I893bdec0b5bba7b620b35678b1c90181d9e4574d
Change-Id: I893bdec0b5bba7b620b35678b1c90181d9e4574d