chore(examples): update imports

examples/nextjs/pages/Undirectional/index.tsx

@@ -1,7 +1,5 @@
 import React, { MouseEvent, useCallback } from 'react';
-
-import {
-  ReactFlow,
+import ReactFlow, {
   useReactFlow,
   NodeTypes,
   addEdge,
@@ -15,6 +13,7 @@ import {
   useNodesState,
   useEdgesState,
 } from 'reactflow';
+
 import CustomNode from './CustomNode';
 
 const initialNodes: Node[] = [