FIX: Ensure group flair upload is present when deciding type (PR #12650)

Previously, if the upload_id was present, but the upload was missing, the entire site would give a server error.

We have no foreign keys on this relation, so we have to be able to cope with the situation where the upload_id is present, but the actual upload has been deleted.

GitHub

    return :image if flair_upload.present?

My idea was to try and avoid a DB query if the flair_upload_id was not present… but in hindsight, flair_upload probably does that sanity check anyway đŸ¤¦

Thanks!