[BUG] 当config的value值为null时，Config表格显示崩溃

![image](https://github.com/SwanHubX/SwanLab/assets/58305964/fb87e1fb-de69-49fb-9203-9ccaacd5b203)

<img width="1442" alt="image" src="https://github.com/SwanHubX/SwanLab/assets/58305964/8cce97d1-18f0-42f3-8255-02bb102ef3ab">


## 🚑 Any additional [like screenshots]

- **SwanLab Version**: v0.2.4

- **Platform**: MacOS
