[功能请求] 添加修改网络在线状态

### QQ(TIM)版本/QQ(TIM) Version

v9.0.65

### 为什么你认为需要此功能

~和修改机型在一起有b格一点~
必要的时候改3g假装网不好

### 联系到哪些已经存在的bug或者功能

自定义机型

### 具体功能需要/Specific features require

杂项新选项

> 启用自定义网络类型

> > 网络类型：_（字符串输入）

如果qq不支持完全自定义的话，固定的选项也不错

Start by locating the existing custom-device-model feature and the code that handles QQ/TIM's displayed network status. Determine whether the app accepts arbitrary network-type strings or only fixed choices. Done means a separate option can enable a custom network type and the selected value is reflected in QQ/TIM.

Written by the indexing model from the issue text.