remove unused plugin (#3661)

Author: Chris Yang

packages/integration_test/example/pubspec.yaml

@@ -24,8 +24,6 @@ dev_dependencies:
     # The example app is bundled with the plugin so we use a path dependency on
     # the parent directory to use the current plugin's version.
     path: ../
-  integration_test_macos:
-    path: ../integration_test_macos
   test: any
   pedantic: ^1.8.0