Add _gat_gtag_UA cookie to gtag cookies array

tarteaucitron.services.js

@@ -871,7 +871,13 @@ tarteaucitron.services.gtag = {
     "name": "Google Analytics (gtag.js)",
     "uri": "https://support.google.com/analytics/answer/6004245",
     "needConsent": true,
-    "cookies": ['_ga', '_gat', '_gid', '__utma', '__utmb', '__utmc', '__utmt', '__utmz'],
+    "cookies": (function () {
+        // Add _gat_gtag_UA_XXXXXXX_XX cookie to cookies array
+        var gatGtagUaCookie = '_gat_gtag_' + tarteaucitron.user.gtagUa;
+        gatGtagUaCookie = gatGtagUaCookie.replace(/-/g, '_');
+        cookies = ['_ga', '_gat', '_gid', '__utma', '__utmb', '__utmc', '__utmt', '__utmz', gatGtagUaCookie];
+        return cookies;
+    })(),
     "js": function () {
         "use strict";
         window.dataLayer = window.dataLayer || [];