feat: Update iOS roadmap link to React Native (#5933)

The iOS roadmap link for React Native was updated to the correct URL. This change ensures that users are directed to the appropriate resource for learning React Native on the iOS roadmap.

Authored-by: kai <trongtoan1609ht@gmail.com>

src/data/roadmaps/ios/ios.json

@@ -6932,7 +6932,7 @@
       "selected": false,
       "data": {
         "label": "React Native",
-        "href": "https://roadmap.sh/flutter",
+        "href": "https://roadmap.sh/react-native",
         "color": "#ffffff",
         "backgroundColor": "#2a79e4",
         "style": {