Modify to ensure that ManagedServices supports concurrent multi-user environments

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 the current user) interacting with driver's display.

Fixes include
- Add new APIs and implement some new logic for operation in a concurrent multi-user environment in Managed Services
- Modify some related logic in ConditionProviders and NotificationManagerService
- Add the DisableFlags annotation for FLAG_MANAGED_SERVICES_CONCURRENT_MULTIUSER to the unit tests that use legacy code

Bug: 380297485
Flag: com.android.server.notification.managed_services_concurrent_multiuser
Test: manual
      atest FrameworksUiServicesTests
      atest CtsLegacyNotification28TestCases --user-type secondary_user_on_secondary_display
      atest CtsLegacyNotification29TestCases --user-type secondary_user_on_secondary_display
      atest CtsNotificationTestCases --user-type secondary_user_on_secondary_display
      atest CtsJobSchedulerTestCases --user-type secondary_user_on_secondary_display
      atest CtsAppTestCases --user-type secondary_user_on_secondary_display
(cherry picked from https://partner-android-review.googlesource.com/q/commit:6b16d795638c4d8d71dc353e17ba53395bbdfefe)

Change-Id: I43de6f294e451ddc6621db3d4dcf283513b053f2