Changes to List offerable number countries

the endpoint scheme security bearerAuth was removed from the API

removed the non-success response with the status 401

the response property countries/items/types/items/tier became nullable for the status 200

added the new undefined enum value to the countries/items/types/items/tier response property for the response status 200

added the optional property countries/items/preOrderable to the response with the 200 status

added the optional property countries/items/types/items/fulfilment to the response with the 200 status

added the optional property countries/items/types/items/preOrderable to the response with the 200 status