Move activities to fullscreen stack on display removal

Instead of moving dynamic stacks from secondary to primary display
on removal, move activities to fullscreen stack. This way activities
are guaranteed to appear in valid launch stack and will respect
split-screen mode bounds.

Bug: 34263289
Bug: 35258038
Test: android.server.cts.ActivityManagerDisplayTests
Test: #testStackFocusSwitchOnDisplayRemoved
Test: #testStackFocusSwitchOnDisplayRemoved2
Change-Id: Iebd3bef3e0cf8afd482630dd5ad8ec4315497950