Use a separate sample set for Toolbar buttons

osu.Game/Graphics/UserInterface/HoverSounds.cs

@@ -68,6 +68,9 @@ namespace osu.Game.Graphics.UserInterface
         Normal,
 
         [Description("-softer")]
-        Soft
+        Soft,
+
+        [Description("-toolbar")]
+        Toolbar
     }
 }

osu.Game/Overlays/Toolbar/ToolbarButton.cs

@@ -77,7 +77,7 @@ namespace osu.Game.Overlays.Toolbar
         private KeyBindingStore keyBindings { get; set; }
 
         protected ToolbarButton()
-            : base(HoverSampleSet.Loud)
+            : base(HoverSampleSet.Toolbar)
         {
             Width = Toolbar.HEIGHT;
             RelativeSizeAxes = Axes.Y;