Move private field for skin editor overlay to where others exist

osu.Game/OsuGame.cs

@@ -80,6 +80,8 @@ namespace osu.Game
 
         private BeatmapSetOverlay beatmapSetOverlay;
 
+        private SkinEditorOverlay skinEditor;
+
         [Cached]
         private readonly DifficultyRecommender difficultyRecommender = new DifficultyRecommender();
 
@@ -946,8 +948,6 @@ namespace osu.Game
 
         private ScalingContainer screenContainer;
 
-        private SkinEditorOverlay skinEditor;
-
         protected override bool OnExiting()
         {
             if (ScreenStack.CurrentScreen is Loader)