Remove unused `ScrollingToolboxGroup` class

osu.Game/Rulesets/Edit/ScrollingToolboxGroup.cs

@@ -1,34 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Game.Graphics.Containers;
-
-namespace osu.Game.Rulesets.Edit
-{
-    public class ScrollingToolboxGroup : EditorToolboxGroup
-    {
-        protected readonly OsuScrollContainer Scroll;
-
-        protected readonly FillFlowContainer FillFlow;
-
-        protected override Container<Drawable> Content { get; }
-
-        public ScrollingToolboxGroup(string title, float scrollAreaHeight)
-            : base(title)
-        {
-            base.Content.Add(Scroll = new OsuScrollContainer
-            {
-                RelativeSizeAxes = Axes.X,
-                Height = scrollAreaHeight,
-                Child = Content = FillFlow = new FillFlowContainer
-                {
-                    RelativeSizeAxes = Axes.X,
-                    AutoSizeAxes = Axes.Y,
-                    Direction = FillDirection.Vertical,
-                },
-            });
-        }
-    }
-}