chore: fix dart format issue

Author: LucasXu0

.github/actions/flutter_build/action.yml

@@ -91,7 +91,14 @@ runs:
 
     - name: Check Dart formatting
       working-directory: frontend/appflowy_flutter
-      run: dart format --output=none --set-exit-if-changed .
+      run: |
+        dart format --output=none --set-exit-if-changed .
+        EXIT_CODE=$?
+        echo "Exit code: $EXIT_CODE"
+        if [ $EXIT_CODE -eq 1 ]; then
+          echo "Error: Dart formatting check failed. Please run 'dart format .' to fix formatting issues."
+          exit 1
+        fi
       shell: bash
 
     - name: Flutter Analyzer