Marks Mac build_android_host_app_with_module_source to be unflaky (fl…

…utter#157412)

<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
{
  "name": "Mac build_android_host_app_with_module_source"
}
-->
The test has been passing for [50 consecutive runs](https://data.corp.google.com/sites/flutter_infra_metrics_datasite/flutter_check_test_flakiness_status_dashboard/?p=BUILDER_NAME:%22Mac%20build_android_host_app_with_module_source%22).
This test can be marked as unflaky.

.ci.yaml

@@ -4115,7 +4115,6 @@ targets:
       - .ci.yaml
 
   - name: Mac build_android_host_app_with_module_source
-    bringup: true
     recipe: devicelab/devicelab_drone
     timeout: 60
     properties: