fix(unicloud-db-contacts): 新增联系人页面, 未关联服务空间或出现未知错误时界面显示{}的问题

pages/component/unicloud-db-contacts/add.uvue

 <template>
   <view class="page">
-    <unicloud-db ref="udb" v-slot:default="{data, loading, error}" :collection="collection" loadtime="manual">
-      <view v-if="error" class="error">{{error}}</view>
+    <unicloud-db ref="udb" v-slot:default="{error}" :collection="collection" loadtime="manual">
+      <view v-if="error!=null" class="error">{{error.errMsg}}</view>
     </unicloud-db>
     <view class="form-item">
       <text class="form-item-label">姓名</text>