bug fix | popconfirm @onConfirm to @confirm

https://github.com/ElemeFE/element/pull/20240



@onConfirm 属性已经去掉了，所以在删除数据集的时候没有作用

Signed-off-by: lengleng <wangiegie@gmail.com>

report-ui/src/views/excelreport/designer/index.vue

@@ -25,7 +25,7 @@
           <el-collapse-item :title="item.setName" :name="item.id">
             <el-popconfirm
               :title="'确定删除' + item.setName + '吗？'"
-              @onConfirm="del(item)"
+              @confirm="del(item)"
             >
               <el-button
                 slot="reference"