fix path to ErrorResponse (#20706)

Author: kristapratico

dev/cognitiveservices/data-plane/Language/questionanswering-generate.json

@@ -123,7 +123,7 @@
           "default": {
             "description": "Error response.",
             "schema": {
-              "$ref": "#/definitions/ErrorResponse"
+              "$ref": "common.json#/definitions/ErrorResponse"
             },
             "headers": {
               "x-ms-error-code": {