Changes to Build cross-chain mint transactions for a drop

the response property receipt_request/relay_request_id became nullable for the status 200

the response property receipt_request/request_id became nullable for the status 200

the response property receipt_request/swap_quote/from_assets/items/token_id became nullable for the status 200

the response property receipt_request/swap_quote/to_assets became nullable for the status 200

the response property receipt_request/swap_quote/to_assets/items/token_id became nullable for the status 200

the response property receipt_request/transaction_identifiers became nullable for the status 200

the response property receipt_request/transaction_identifiers/items/swap_provider became nullable for the status 200

the response property transactions/items/to became nullable for the status 200

the response property transactions/items/value became nullable for the status 200

the response property transactions/items/value_hex became nullable for the status 200

added the non-success response with the status 503

added the optional property code to the response with the 400 status

added the optional property code to the response with the 401 status

added the optional property code to the response with the 403 status

added the optional property code to the response with the 404 status

added the optional property code to the response with the 409 status

added the optional property code to the response with the 422 status

added the optional property transactions/items/gas_limit to the response with the 200 status

added the optional property transactions/items/svm to the response with the 200 status