Throw on OsuClickableContainer.ClearInternal() invocations

As they may cause critical failure due to getting rid of the `Content`.

osu.Game/Graphics/Containers/OsuClickableContainer.cs

@@ -1,6 +1,7 @@
 // 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 System;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -46,5 +47,8 @@ namespace osu.Game.Graphics.Containers
             AddInternal(content);
             Add(CreateHoverSounds(sampleSet));
         }
+
+        protected override void ClearInternal(bool disposeChildren = true) =>
+            throw new InvalidOperationException($"Clearing {nameof(InternalChildren)} will cause critical failure. Use {nameof(Clear)} instead.");
     }
 }