chore: update pubspec versions after dependency changes

- Update example and platform interface pubspec files
- Ensure version consistency across packages

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ened

example/pubspec.yaml

@@ -18,8 +18,6 @@ dependencies:
 dev_dependencies:
   integration_test:
     sdk: flutter
-  flutter_test:
-    sdk: flutter
   flutter_lints: ^6.0.0
 
 flutter:

workmanager_platform_interface/pubspec.yaml

@@ -17,8 +17,6 @@ dependencies:
   plugin_platform_interface: ^2.1.0
 
 dev_dependencies:
-  flutter_test:
-    sdk: flutter
   flutter_lints: ^6.0.0
   pigeon: ^22.6.0