fix: tree组件显示异常

lib/component/tree/tree-api.vue

@@ -1,11 +1,11 @@
 <template>
   <a-spin :spinning="treeState.loading">
     <div class="ns-tree-form">
-      <div v-show="header" class="ns-tree-title">
+      <div v-if="header" class="ns-tree-title">
         <ns-icon :name="header.icon" size="14" />
         <span>{{ header.title }}</span>
       </div>
-      <div v-show="!formConfig?.schema">
+      <div v-if="!formConfig?.schema">
         <ns-form ref="formElRef" v-bind="formConfig" :model="formModel" @finish="formFinish" />
       </div>
     </div>