[Bug] The proxy server settings should include an availability check

### Contact Information

_No response_

### 1Panel Version

v2

### Problem Description

误输入了无效的端口，保存后面板将直接无法访问

### Steps to Reproduce

面板设置 > 代理服务器 中配置代理

### The expected correct result

_No response_

### Related log output

```shell

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### Additional Information

_No response_