Throws an Error when used without Git

**Describe the bug**
When using a VCS like JJ, the extension crashes with "Unable to Connect to the GitHub API, please check your internet connection."

**To Reproduce**
Steps to reproduce the behavior:
1. Put `git.disabled` in your .vscode/settings.json
2. Open actions pane

**Expected behavior**
It shouldn't require the Git extension, only provide optional features (like current branch).

**Screenshots**
```
2025-03-14 12:38:40.980 [error] Error: Git model not found
at s.getAPI (/Users/dukese01/Applications/Visual Studio Code.app/Contents/Resources/app/extensions/git/dist/main.js:2:805076)
at new _d (/Users/dukese01/.vscode/extensions/github.vscode-pull-request-github-0.106.0/dist/extension.js:2190:26346)
at Function.createProvider (/Users/dukese01/.vscode/extensions/github.vscode-pull-request-github-0.106.0/dist/extension.js:2190:26938)
at gw (/Users/dukese01/.vscode/extensions/github.vscode-pull-request-github-0.106.0/dist/extension.js:2190:32572)
at kf (/Users/dukese01/.vscode/extensions/github.vscode-pull-request-github-0.106.0/dist/extension.js:2526:6481)
at G4 (/Users/dukese01/.vscode/extensions/github.vscode-pull-request-github-0.106.0/dist/extension.js:2526:7586)
```

**Extension Version**
`v0.27.1`

**Additional context**
Feel free to close as wontfix, I know this isn't exactly the recommended workflow :)
As I think about it, can you even figure out the connected repo without Git? IDK.

Reproduce the crash by setting git.disabled in .vscode/settings.json and opening the actions pane. Trace the extension startup path that creates the Git-dependent provider, then verify that the actions pane opens without the Git extension while optional features such as the current branch can be unavailable.

由索引模型根據 Issue 內容生成。