[Bug] MQTT cant use new user except root!!

### Search before asking

- [X] I searched in the [issues](https://github.com/apache/iotdb/issues) and found nothing similar.

### Version

1.2.*

### Describe the bug and provide the minimal reproduce step

when create a new user in iotdb, it can login iotdb server,but cant use MQTT by this user

### What did you expect to see?

need to use other user to use MQTT

### What did you see instead?

null

### Anything else?

_No response_

### Are you willing to submit a PR?

- [ ] I'm willing to submit a PR!

报告提到了 IoTDB 1.2.* 和 MQTT，但没有提供文件、测试或入口点。首先使用新创建的 non-root 用户复现 MQTT 访问，并将其与 root 访问进行比较；完成的标准是 non-root 用户能够成功使用 MQTT。

由索引模型根据 Issue 内容生成。