Changes to Retrieve destinations

the response property models/items/config/oneOf[#/components/schemas/DestinationTypeConfigHTTP]/delivery_groups/rate_limit became required for the status 200

the response property models/items/config/oneOf[#/components/schemas/DestinationTypeConfigHTTP]/delivery_groups/rate_limit_period became required for the status 200

the response property models/items/config/oneOf[#/components/schemas/DestinationTypeConfigMOCK_API]/delivery_groups/rate_limit became required for the status 200

the response property models/items/config/oneOf[#/components/schemas/DestinationTypeConfigMOCK_API]/delivery_groups/rate_limit_period became required for the status 200