Add track_total_hits to search_mvt (#4850)

(cherry picked from commit 069159f)

Author: pquentin

output/openapi/elasticsearch-openapi.json

@@ -43,8 +43,7 @@
     },
     "search_mvt": {
       "request": [
-        "Request: query parameter 'grid_agg' does not exist in the json spec",
-        "Request: missing json spec query parameter 'track_total_hits'"
+        "Request: query parameter 'grid_agg' does not exist in the json spec"
       ],
       "response": []
     },

output/openapi/elasticsearch-serverless-openapi.json

@@ -200,6 +200,13 @@ export interface Request extends RequestBase {
      * @server_default 10000
      */
     size?: integer
+    /**
+     * The number of hits matching the query to count accurately.
+     * If `true`, the exact number of hits is returned at the cost of some performance.
+     * If `false`, the response does not include the total number of hits matching the query.
+     * @server_default 10000
+     */
+    track_total_hits?: TrackHits
     /**
      * If `true`, the hits and aggs layers will contain additional point features representing
      * suggested label positions for the original features.