Move display order of focused stack to top when updating focus

Now focused stack depends on the order of display, so if a stack
is expected to be focused, its display should also move to top.

Bug: 111818977
Test: atest CtsActivityManagerDeviceTestCases:ActivityManagerMultiDisplayTests
Test: atest FrameworksServicesTests:ActivityStackSupervisorTests
Change-Id: I38e0aa4a78712561ab796b6522b733421286b7d9