Integrations: don't send build status for builds without a version (#12750)
There is a race condition when deleting a version. Not really sure how
this happens, like we only delete external versions when a project is
deleted or when the delete_closed_external_versions task is called... If
a project is deleted, the build should be deleted as well, and we don't
even have that many versions left to delete to say that two tasks are
overlapping. Anyway, it doesn't make sense to report a build status over
a build that doesn't have a version.
Fixes
https://read-the-docs.sentry.io/issues/5762982757/?project=161479&query=%21logger%3Acsp%20is%3Aunresolved&referrer=issue-stream