Update merge button text
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/24559
Rest of updates in addition to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8005
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/24559
Rest of updates in addition to https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/8005