Marks Linux_android very_long_picture_scrolling_perf__e2e_summary to be unflaky (#134116)

<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
{
  "name": "Linux_android very_long_picture_scrolling_perf__e2e_summary"
}
-->
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_android%20very_long_picture_scrolling_perf__e2e_summary%22).
This test can be marked as unflaky.

.ci.yaml

@@ -2124,7 +2124,6 @@ targets:
 
   - name: Linux_android very_long_picture_scrolling_perf__e2e_summary
     recipe: devicelab/devicelab_drone
-    bringup: true
     presubmit: false
     timeout: 120
     properties: