text: Title: GraphicsScene.mouseMoveEvent duplicates events
  Body: The current implementation of GraphicsScene.mouseMoveEvent calls the base class implementation twice, when QMouseEvent.buttons() is something else than Qt.MouseButton.NoButton. The duplicate call happens here:
  
  https://github.com/pyqtgraph/pyqtgraph/blob/88c3127ddf021407bdfedbbfff898036dd84df79/pyqtgraph/GraphicsScene/GraphicsScene.py#L182
  
  I don’t see any reason at this point to call the base class handler again. In general, I think the events should be duplicated and handled twice.