Exclude opening/move-to-front task from exiting immersive

It's possible for a non-top task to be moved to front and enter
immersive at the same time, so exclude it in move-to-front or opening
WCT from exiting immersive mode, since it doesn't make sense to exit
immersive in those cases.

Flag: com.android.window.flags.enable_fully_immersive_in_desktop
Fix: 374772576
Test: open Candy Crush in desktop, enter immersive, open settings from
notification shade, close settings, put candy crash back in immersive
and verify the app header can't be dragged or double clicked.

Change-Id: I9f614065814dcfbb2bae347ba00c10a53cdae71a