fix: handle Channel.DoesNotExist in remove_self#5769

bjester merged 1 commit intolearningequality:unstablelearningequality/studio:unstablefrom

ashnaaseth2325-oss:fix/channel-does-not-exist-remove-selfashnaaseth2325-oss/studio:fix/channel-does-not-exist-remove-selfCopy head branch name to clipboard