style: 删除冗余代码

src/views/components/MyMxGraph/index.vue

@@ -1,6 +1,5 @@
 <template>
   <div class="app-container">
-    <h1>mxGraph 图形编辑器</h1>
     <div class="mx-toolbar">
       <button><span class="icon">+</span> 放大</button>
       <button><span class="icon">-</span> 缩小</button>