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.

.vscode/settings.json で git.disabled を設定してアクション ペインを開き、クラッシュを再現します。Git に依存するプロバイダーを作成する拡張機能の起動経路を追跡し、その後、Git 拡張機能なしでアクション ペインが開くことを確認します。ただし、現在のブランチなどのオプション機能は利用できない場合があります。

索引モデルが issue の本文から書いたものです。