build: use stable Flutter channel for deploy

- Changed flutter channel to stable

Author: fulleni

.github/workflows/deploy.yml

@@ -17,7 +17,7 @@ jobs:
       - name: Setup Flutter
         uses: subosito/flutter-action@v2
         with:
-          channel: 'beta' # Use the stable channel of Flutter
+          channel: 'stable' # Use the stable channel of Flutter
           cache: false
 
       # 3. Get Flutter dependencies