Marks Linux_samsung_a02 new_gallery__transition_perf to be unflaky (flutter#135373)

<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
{
  "name": "Linux_samsung_a02 new_gallery__transition_perf"
}
-->
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:%22Linux_samsung_a02%20new_gallery__transition_perf%22).
This test can be marked as unflaky.

Author: fluttergithubbot

.ci.yaml

@@ -2426,7 +2426,6 @@ targets:
   # Samsung A02, Skia
   - name: Linux_samsung_a02 new_gallery__transition_perf
     recipe: devicelab/devicelab_drone
-    bringup: true
     presubmit: false
     timeout: 60
     properties: