Marks Linux_pixel_7pro drive_perf_debug_warning to be flaky (flutter#174112)

<!-- meta-tags: To be used by the automation script only, DO NOT MODIFY.
{
  "name": "Linux_pixel_7pro drive_perf_debug_warning"
}
-->
Issue link: flutter#174111

Author: fluttergithubbot

.ci.yaml

@@ -2711,6 +2711,7 @@ targets:
       task_name: devtools_profile_start_test
 
   - name: Linux_pixel_7pro drive_perf_debug_warning
+    bringup: true # Flaky https://github.com/flutter/flutter/issues/174111
     recipe: devicelab/devicelab_drone
     presubmit: false
     timeout: 60