Add integration test for the Platform Services app (#8826)

examples/platform_services/pubspec.yaml

diff --git a/examples/platform_services/pubspec.yaml b/examples/platform_services/pubspec.yaml
index a889233..fd42143 100644
--- a/examples/platform_services/pubspec.yaml
+++ b/examples/platform_services/pubspec.yaml
@@ -7,6 +7,8 @@
 dev_dependencies:
   flutter_test:
     sdk: flutter
+  flutter_driver:
+    path: ../../packages/flutter_driver
 
 flutter:
   uses-material-design: true