Marks Linux_android flutter_gallery__start_up_delayed to be flaky (#134632)

<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
{
  "name": "Linux_android flutter_gallery__start_up_delayed"
}
-->
Issue link: https://github.com/flutter/flutter/issues/134631

.ci.yaml

@@ -2104,6 +2104,7 @@ targets:
       task_name: flutter_gallery__start_up
 
   - name: Linux_android flutter_gallery__start_up_delayed
+    bringup: true # Flaky https://github.com/flutter/flutter/issues/134631
     recipe: devicelab/devicelab_drone
     presubmit: false
     timeout: 60