Changes to List nfts

the response property _status/messages/items/data became nullable for the status 400

the response property _status/messages/items/detail became nullable for the status 400

the response property links/next became nullable for the status 200

the response property nfts/items/account_id became nullable for the status 200

the response property nfts/items/created_timestamp became nullable for the status 200

the response property nfts/items/delegating_spender became nullable for the status 200

the response property nfts/items/modified_timestamp became nullable for the status 200

the response property nfts/items/spender became nullable for the status 200

the response property nfts/items/token_id became nullable for the status 200