Add changelog for LDAP settings update
Adds a changelog item that should have been added in https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/1624#note_35978835.
Do not update/delete: Banner broadcast message test data
Do not update/delete: Notification broadcast message test data
Adds a changelog item that should have been added in https://gitlab.com/gitlab-org/omnibus-gitlab/merge_requests/1624#note_35978835.