Fix tiny nme crash when a node was not part of the graph

nodeEditor/src/diagram/graphCanvas.tsx

@@ -414,6 +414,9 @@ export class GraphCanvasComponent extends React.Component<IGraphCanvasComponentP
         // Update graph
         let dagreNodes = graph.nodes().map(node => graph.node(node));
         dagreNodes.forEach((dagreNode: any) => {
+            if (!dagreNode) {
+                return;
+            }
             if (dagreNode.type === "node") {
                 for (var node of this._nodes) {
                     if (node.id === dagreNode.id) {