Changes to Get All Cross Margin Pairs (MARKET_DATA)

added the new required query request parameter symbol

the response property code became required for the status 400

the response property items/base became required for the status 200

the response property items/id became required for the status 200

the response property items/isBuyAllowed became required for the status 200

the response property items/isMarginTrade became required for the status 200

the response property items/isSellAllowed became required for the status 200

the response property items/quote became required for the status 200

the response property items/symbol became required for the status 200

the response property msg became required for the status 400