🐞 GitLab SelfHosted: Can't add account

### Description

Hi there,

I'm not able to add the GitLab Self Hosted account, in the terminal there is this warning

`git auth failure: dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "Unexpected character '<' around line 1, column 1." UserInfo={NSDebugDescription=Unexpected character '<' around line 1, column 1., NSJSONSerializationErrorIndex=0})))
`

### To Reproduce

1. Go to Settings;
2. Navigate to Account;
3. Click on Add account;
4. Select GitLab SelfHosted
5. Insert as host: https://git.offertetou********.com/
6. Insert My User name (andrea.calabro at offertetou********.com)
7. Insert My Personal Token;
8. Click on Sign In
9. Error

### Expected Behavior

Login to my Self hosted GitLab

### Version Information

CodeEdit: Version 0.1.0-alpha (38)
macOS: 14.5 (23F79)

### Additional Context

_No response_

### Screenshots

從 GitLab SelfHosted 的 Settings > Account > Add account 流程開始，使用 self-hosted 主機、使用者名稱和個人 token 重現回報的登入問題。檢查終端機解碼警告以及驗證期間傳回的回應；完成的條件是能夠成功新增有效的 self-hosted GitLab 帳戶，而不是產生 JSON 解碼錯誤。

由索引模型根據 Issue 內容生成。