Marks Mac_android microbenchmarks to be unflaky (#119727)

Author: fluttergithubbot

.ci.yaml

@@ -3327,7 +3327,6 @@ targets:
       task_name: integration_ui_frame_number
 
   - name: Mac_android microbenchmarks
-    bringup: true # Flaky https://github.com/flutter/flutter/issues/118692
     recipe: devicelab/devicelab_drone
     presubmit: false
     timeout: 60