Fix: Fixed the issue where the operator added by clicking the plus sign in the data flow would overlap with the original section #9886 (#10458)

### What problem does this PR solve?

Fix: Fixed the issue where the operator added by clicking the plus sign
in the data flow would overlap with the original section #9886

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/pages/data-flow/canvas/index.tsx

@@ -178,11 +178,17 @@ function DataFlowCanvas({ drawerVisible, hideDrawer, showLogSheet }: IProps) {
   };
 
   const onConnectEnd: OnConnectEnd = (event, connectionState) => {
+    const target = event.target as HTMLElement;
     const nodeId = connectionState.fromNode?.id;
+
     // Events triggered by Handle are directly interrupted
-    if (connectionState.toNode !== null || (nodeId && hasChildNode(nodeId))) {
+    if (
+      target?.classList.contains('react-flow__handle') ||
+      (nodeId && hasChildNode(nodeId))
+    ) {
       return;
     }
+
     if ('clientX' in event && 'clientY' in event) {
       const { clientX, clientY } = event;
       setDropdownPosition({ x: clientX, y: clientY });