Fix UiModeManagerTest for secondary_user_on_secondary_display

UiMode does not support visible background users at the moment.
Apply two fixes:
- Skip existing test cases for visible background users.
- Add test cases to check whether a security exception occurs when visible background users use UiMode.

Bug: 340960913
Flag: EXEMPT test fix
Test: atest CtsAppTestCases:UiModeManagerTest
Test: atest --user-type secondary_user CtsAppTestCases:UiModeManagerTest
Test: atest --user-type secondary_user_on_secondary_display CtsAppTestCases:UiModeManagerTest
(cherry picked from https://partner-android-review.googlesource.com/q/commit:8aa1559497afaaa5115e1dba1489373ccb10d48a)
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:a9cfe9198d82d4db8d1b41f9e689a5e01814ca49)
Merged-In: I5c8b41debfdf40c71a3279354b08c3fe8dcc6975
Change-Id: I5c8b41debfdf40c71a3279354b08c3fe8dcc6975