修复邮件消息通知bug

src/views/system/mail/template/MailTemplateForm.vue

@@ -115,6 +115,7 @@ const onChange = async (field, cur) => {
 }
 
 const resetReceiverType = () => {
+  if (!formRef.value) return
   // 初始化设置值
     const setV = {
       roleIdList: [],