Overview: Only trigger middle click close with mouse/pen

For some reason, while touch doesn't have a middle button, the
taphandler for middle click close still triggered on tap. So make it
explicitly only support mouse/pen so we exclude touch events.

BUG: 445755

src/effects/overview/qml/WindowHeap.qml

@@ -204,6 +204,7 @@ FocusScope {
                 }
 
                 TapHandler {
+                    acceptedPointerTypes: PointerDevice.GenericPointer | PointerDevice.Pen
                     acceptedButtons: Qt.MiddleButton
                     onTapped: thumb.client.closeWindow()
                 }