Add support for excluding users in DocumentsUI results

This commit integrates support for the `DocumentsContract.EXTRA_EXCLUDED_USERS` intent extra, allowing calling applications to hide specific user profiles from the file picker UI.

Bug: 400701044
Test: manual
Test: atest CtsProviderUiTestCases

Flag: android.multiuser.enable_moving_content_into_private_space

Change-Id: I01c56ddca9292a62446b39a96339c1fdd9285993