Removed field that is not used in the request (Azure#16593)

Author: omrodrig

specification/cost-management/resource-manager/Microsoft.CostManagement/stable/2019-11-01/costmanagement.json

@@ -2713,10 +2713,6 @@
             "modelAsString": true
           }
         },
-        "configuration": {
-          "description": "Has configuration information for the data in the export. The configuration will be ignored if aggregation and grouping are provided.",
-          "$ref": "#/definitions/QueryDatasetConfiguration"
-        },
         "aggregation": {
           "type": "object",
           "description": "Dictionary of aggregation expression to use in the query. The key of each item in the dictionary is the alias for the aggregated column. Query can have up to 2 aggregation clauses.",