fix(消息通知): 修复测试计划执行结束后没有给执行人发通知的问题

--bug=1013979 --user=刘瑞斌 【消息通知】设置测试计划执行成功的邮件通知特定测试计划收不到消息 https://www.tapd.cn/55049933/s/1187352

backend/src/main/java/io/metersphere/notice/sender/impl/MailNoticeSender.java

@@ -96,12 +96,24 @@ public class MailNoticeSender extends AbstractNoticeSender {
 
         LogUtil.info("收件人地址: {}", Arrays.asList(users));
         helper.setText(context, true);
-        helper.setTo(users);
+        // 有抄送
         if (cc != null && cc.length > 0) {
             helper.setCc(cc);
-        }
+            helper.setTo(users);
             javaMailSender.send(mimeMessage);
         }
+        // 无抄送
+        else {
+            for (String u : users) {
+                helper.setTo(u);
+                try {
+                    javaMailSender.send(mimeMessage);
+                } catch (Exception e) {
+                    LogUtil.error("发送邮件失败: ", e);
+                }
+            }
+        }
+    }
 
     public void sendExternalMail(String context, NoticeModel noticeModel) throws Exception {