ref: CommitContextClient methods accept repository instance

[jianyuan]

The issue is that repo.name works well for GitHub (it’s in the format getsentry/sentry, which can be used in the API URL path), whereas repo.name in GitLab is name_with_namespace (formatted as Get Sentry / Sentry), which is not suitable for use in the URL path.

GitLab, in particular, offers an option to use the internal project_id in URL paths.
https://docs.gitlab.com/api/commits/#list-merge-requests-associated-with-a-commit

I propose a change to make the get_merge_commit_sha_from_commit accept a more generic instance of Repository, leaving the implementation details to the integration. I've also adjusted CommitContextIntegration.queue_comment_task_if_needed which uses this method accordingly.