Update Flutter workflow to use channel parameter and add version output

Co-authored-by: java-james <22756998+java-james@users.noreply.github.com>

Author: Copilot

.github/workflows/flutter-tests.yml

@@ -18,14 +18,17 @@ jobs:
     - name: Checkout code
       uses: actions/checkout@v4
 
-    - name: Setup Flutter
+    - name: Set up Flutter
       uses: subosito/flutter-action@v2
       with:
-        flutter-version: stable
+        channel: stable
         cache: true
         cache-key: flutter-${{ hashFiles('**/pubspec.lock') }}
         cache-path: ${{ runner.tool_cache }}/flutter
 
+    - name: Show Flutter version
+      run: flutter --version
+        
     - name: Get dependencies
       run: flutter pub get