Marks Mac_ios new_gallery_ios__transition_perf to be unflaky (#105627)

Author: fluttergithubbot

.ci.yaml

@@ -3472,7 +3472,6 @@ targets:
     scheduler: luci
 
   - name: Mac_ios new_gallery_ios__transition_perf
-    bringup: true # Flaky https://github.com/flutter/flutter/issues/96401
     recipe: devicelab/devicelab_drone
     presubmit: false
     timeout: 60