[BUG Report] 左侧导航不支持自动显示滚动条

### Description

MList缺少一下样式，border的样式有冲突。

``` css
overflow-y: scroll;
height: calc(100% - 132px);
overflow-x: hidden;
```

### Screenshots

_No response_

### OS version

_No response_

### Visual Studio version

_No response_

### Additional context

_No response_