UI: Rainbow cycling speed settings

Note: this setting is global, even though it appears in the settings for the individual gamepad. This is simply for consistency; you access all the rainbow stuff in one place.

src/Ryujinx/Utilities/Configuration/ConfigurationState.Migration.cs

@@ -140,6 +140,7 @@ namespace Ryujinx.Ava.Utilities.Configuration
             Hid.EnableMouse.Value = cff.EnableMouse;
             Hid.Hotkeys.Value = cff.Hotkeys;
             Hid.InputConfig.Value = cff.InputConfig ?? [];
+            Hid.RainbowSpeed.Value = cff.RainbowSpeed;
 
             Multiplayer.LanInterfaceId.Value = cff.MultiplayerLanInterfaceId;
             Multiplayer.Mode.Value = cff.MultiplayerMode;
@@ -427,7 +428,8 @@ namespace Ryujinx.Ava.Utilities.Configuration
                             LedColor = new Color(255, 5, 1, 253).ToUInt32()
                         };
                     }
-                })
+                }),
+                (62, static cff => cff.RainbowSpeed = 1f)
             );
     }
 }