actiontypes bug fix

frontend/src/types/ActionTypes.ts

@@ -291,6 +291,7 @@ reconnectOrRemoveNextNodes(targetNode: IActionNode): void {
   //二つ以上の場合
   for(const [point,nextid] of nextNodeIds){
     const nextNode = this.findNodeById(nextid);
+    if(!nextNode) return;
     if(!this.connectNodes(prevNode,nextNode,point)){
       this.removeAllNext(nextid);
       this.removeFromActionNodes(nextid);