Fix rest spec for graph explore

Original commit: elastic/x-pack-elasticsearch@293b5c9ebd

elasticsearch/x-pack/graph/src/test/resources/rest-api-spec/api/xpack.graph.explore.json

@@ -3,8 +3,8 @@
     "documentation": "https://www.elastic.co/guide/en/graph/current/explore.html",
     "methods": ["GET", "POST"],
     "url": {
-      "path": "/{index}/_xpack/graph/_explore",
-      "paths": ["/{index}/_xpack/graph/_explore", "/{index}/{type}/_xpack/graph/_explore"],
+      "path": "/{index}/_xpack/_graph/_explore",
+      "paths": ["/{index}/_xpack/_graph/_explore", "/{index}/{type}/_xpack/_graph/_explore"],
       "parts" : {
         "index": {
          "type" : "list",