qml: consider horizontal wheel events in `WheelToVLCConverter` of `VolumeWidget.qml`

modules/gui/qt/player/qml/controlbarcontrols/VolumeWidget.qml

@@ -322,12 +322,17 @@ T.Pane {
                 WheelToVLCConverter {
                     id: wheelToVLC
 
-                    onWheelUpDown: (steps, modifiers) => {
+                    function handle(steps: int) {
                         if (steps > 0)
                             Player.setVolumeUp(steps)
                         else
                             Player.setVolumeDown(-steps)
                     }
+
+                    Component.onCompleted: {
+                        wheelUpDown.connect(wheelToVLC.handle)
+                        wheelLeftRight.connect(wheelToVLC.handle)
+                    }
                 }
             }
         }