Render "View on Bitbucket Cloud" links in the UI

Created by: flying-robot

For some reason, this wasn't included in the case statement for possible external URLs, so the frontend was always receiving an empty array and wouldn't render any "View on Bitbucket Cloud" links.

With this change, I'm able to browse to a Bitbucket Cloud repository locally and get a complete "View on Bitbucket Cloud" option in the UI, which takes me to the correct location for the repo, individual files and at specific commits.

ref https://github.com/sourcegraph/sourcegraph/issues/20819