can't trigger workflow run when in sub directory of git repository

**Describe the bug**

If you open the sub directory of a git repository, click `Trigger workflow` button will do nothing. But can trigger in the root directory of the repository.

**Extension Version**

v0.26.3

Reproduce the issue in VS Code using extension version v0.26.3, comparing the Trigger workflow button in a repository root and a subdirectory. Start from the Trigger workflow command or button entry point; done means the workflow can be triggered successfully from both locations.

由索引模型根据 Issue 内容生成。