Changes to GET /private/get_subaccounts_details

the error response's property type changed from integer to object for status 401

removed the required property message from the response with the 401 status

added the optional property error/data to the response with the 401 status

added the required property error/code to the response with the 401 status

added the required property error/message to the response with the 401 status

the result/items/positions/items/leverage response's property type changed from integer to number for status 200

added the required property result/items/positions/items/user_id to the response with the 200 status

added the optional property result/items/open_orders/items/starbase_client_order_id to the response with the 200 status