Change cancel_invited_user client to not return anything.
Change cancel_invited_user client to not return anything.

alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,alphagov/notifications-admin,alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,alphagov/notifications-admin,gov-cjwaszczuk/notifications-admin,gov-cjwaszczuk/notifications-admin