Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Documents https://gitlab.com/gitlab-com/www-gitlab-com/commit/08a06fe0874c3fc2bd42d9683e9f69271d84d527 from https://gitlab.com/gitlab-com/www-gitlab-com/merge_requests/5804
merged
mentioned in commit 6920e4b9