Added link to Firebase Remote Config

docs/en/en.json

@@ -991,6 +991,10 @@
                         "path": "/extension-firebase-analytics",
                         "name": "Firebase Analytics"
                     },
+                    {
+                        "path": "/extension-firebase-remoteconfig",
+                        "name": "Firebase Remote Config"
+                    },
                     {
                         "path": "/extension-gpgs",
                         "name": "Google Play Game Services"