GitHub Enterprise sign-in prompt silently missing when repo has GitHub-style remote but github-enterprise.uri unset

Environment

• Extension version: 0.156.0
• VS Code Version: 1.121.0-insider
• OS: macOS (Darwin)
• Repository Clone Configuration: single repository, cloned via SSH
• GitHub Product: GitHub Enterprise Server

Steps to Reproduce

1. Open a folder whose git remote is a GitHub Enterprise Server repo over SSH (e.g. ssh://git@ghe.example.com/org/repo.git), without ever having set github-enterprise.uri.
2. Open the "GitHub Pull Requests" / Source Control view.
3. Observe the sign-in area of the view.

Expected behavior

Some sign-in prompt or message appears, so there's something to act on.

Actual behavior

The view renders completely empty — no button, no message, no error. There's nothing to click and no indication of what's wrong.

Manually setting github-enterprise.uri to the GHE server's base URL (e.g. https://ghe.example.com) in settings.json makes it work. I don't know if that's the right way to do it or if that's documented.