Avalonia: Make slider scrollable with mouse wheel (#5760)

* Add scrollable custom control based on TickFrequency

* Use custom slider to update value when pointer wheel scrolled

* Remove extra xaml file

* Address formatting issues

* Only scroll one element at a time

* Add OnPointerWheelChanged event to VolumeStatus button

Co-authored-by: Ahmad Tantowi <ahmadtantowi@outlook.com>

---------

Co-authored-by: TSR Berry <20988865+TSRBerry@users.noreply.github.com>

src/Ryujinx.Ava/UI/Controls/SliderScroll.axaml.cs

@@ -0,0 +1,31 @@
+using Avalonia.Controls;
+using Avalonia.Input;
+using System;
+
+namespace Ryujinx.Ava.UI.Controls
+{
+    public class SliderScroll : Slider
+    {
+        protected override Type StyleKeyOverride => typeof(Slider);
+
+        protected override void OnPointerWheelChanged(PointerWheelEventArgs e)
+        {
+            var newValue = Value + e.Delta.Y * TickFrequency;
+
+            if (newValue < Minimum)
+            {
+                Value = Minimum;
+            }
+            else if (newValue > Maximum)
+            {
+                Value = Maximum;
+            }
+            else
+            {
+                Value = newValue;
+            }
+
+            e.Handled = true;
+        }
+    }
+}