Do not change scene when launching edit mode in STF

When scene container is disabled, the communal scene is rendered in
notifications shade over everything so needs to be hidden when edit mode
is launched. With scene container, hidding the scene container is
handled by STF so we do not need to manually do it.

Test: verified that edit mode is started correctly
Test: verified that upon dismissing edit mode, the screen goes back to
      GH. The device is however not locked which is tracked at b/365596274
Bug: 356141092
Flag: com.android.systemui.scene_container
Change-Id: I1bb8fdf7bcaa49f58f9c1296941396801e9e20f7