Previously, checking if a repository is a GitHub remote required an
active branch. In a detached HEAD or mid-rebase state (where the branch
is null), the probe never resolved, leaving the PR panel on a forever
spinner.
Decouple the repository probe from the branch presence so the panel
can correctly display the "Current branch unavailable" state. Also,
hide the PR status chip when no branch is active to avoid a spinner
on the chip.
Jinjing
6fbfeeb2e4