Changes to List themes

api operation id listThemes was added

the response property pagination/nextCursor became required for the status 200

the response property pagination/nextPage became required for the status 200

the response property pagination/perPage became required for the status 200

the response property pagination/returnedResults became required for the status 200

the response property pagination/totalPages became required for the status 200

the response property pagination/totalResults became required for the status 200