updating flutter versiob to 3.38.4

Author: Paul Philion

.github/workflows/webpreview.yaml

@@ -26,7 +26,7 @@ jobs:
       uses: subosito/flutter-action@v2
       with:
         channel: stable
-        flutter-version: '3.24.5'
+        flutter-version: '3.38.4'
     - run: flutter pub get
     # original values are in deployment/values.cloud.yaml
     - run: flutter build web --web-renderer html --dart-define=SUPABASE_ANON_KEY=${{ secrets.CLOUD_DB_JWT_ANON_KEY}} --dart-define=SUPABASE_URL=${{ secrets.CLOUD_DB_URL}}