crashed when click twice on a no-connection-port of locked-node

[mindon]

using example lock_nodes_and_connections

MBP M1, MacOS 13.5 Qt6.5.1

Repeat Steps:

1. create a node
2. locked nodes
3. click on one empty port twice (a port without a connection)

Logs:

0   QtWidgets                     	       0x1032d5198 QGraphicsItem::acceptedMouseButtons() const + 4
1   QtWidgets                     	       0x1032f78ec QGraphicsScenePrivate::mousePressEventHandler(QGraphicsSceneMouseEvent*) + 796
2   QtWidgets                     	       0x1032fd9a0 QGraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent*) + 88
3   QtWidgets                     	       0x1032facac QGraphicsScene::event(QEvent*) + 724
4   QtWidgets                     	       0x10301a628 QApplicationPrivate::notify_helper(QObject*, QEvent*) + 272
5   QtWidgets                     	       0x10301b4c8 QApplication::notify(QObject*, QEvent*) + 560
6   QtCore                        	       0x1036d6db8 QCoreApplication::notifyInternal2(QObject*, QEvent*) + 208
7   QtWidgets                     	       0x103321498 QGraphicsView::mousePressEvent(QMouseEvent*) + 508
8   libQtNodes.dylib              	       0x1028d39a4 QtNodes::GraphicsView::mousePressEvent(QMouseEvent*) + 36