[Flexiglass] Flag off closing RemoteInput controls from CentralSurfaces

Closing the keyboard activated by the remote input field on the
notification is now handled through
SceneContainerViewModel#onEmptySpaceMotionEvent(motionEvent: MotionEvent).

Fixes: 430341437
Test: activate remote input on a notification -> close it by clicking an
empy area
Flag: com.android.systemui.scene_container

Change-Id: I4557c79d8d6c33a615ab8d0fc78f4d4a969e9939