Fixed UserVisibilityMediator profile scenario.

A profile should not started visible when its parent is not visible.

Also made some cosmetic improvements (like javadoc clarification and
setting DBG dynamically).

Test: atest UserVisibilityMediatorSUSDTest UserVisibilityMediatorMUMDTest UserVisibilityMediatorMUPANDTest
Test: atest android.server.wm.StartActivityAsUserTests#startActivityAsValidUserWithOptions

Bug: 261538337

Change-Id: Ib29d1230eb592eb2583fb7878acb2eb7b0c7cf73
5 files changed