Change Flutter setup action in workflow

Updated the workflow to use the dart-lang/setup-dart action instead of subosito/flutter-action for setting up Flutter.

Author: lgund

.github/workflows/flutter-web.yml

@@ -17,10 +17,12 @@ jobs:
       - name: Checkout Repository
         uses: actions/checkout@v4
 
+      # Note: This workflow uses the latest stable version of the Dart SDK.
+      # You can specify other versions if desired, see documentation here:
+      # https://github.com/dart-lang/setup-dart/blob/main/README.md
+      # - uses: dart-lang/setup-dart@v1
       - name: Set up Flutter
-        uses: subosito/flutter-action@v2
-        with:
-          flutter-version: "stable"
+        uses: dart-lang/setup-dart@9a04e6d73cca37bd455e0608d7e5092f881fd603
 
       - name: Install dependencies
         run: flutter pub get