[fenix] Bug 1632427 - Define artifact_prefix in browsertime task (https://github.com/mozilla-mobile/fenix/pull/10151)

taskcluster/ci/browsertime/kind.yml

@@ -20,6 +20,8 @@ only-for-abis:
     - arm64-v8a
 
 job-defaults:
+    attributes:
+        artifact_prefix: public/test_info
     dependencies:
         geckoview-nightly: geckoview-nightly
     notify:

taskcluster/fenix_taskgraph/transforms/visual_metrics.py

@@ -64,10 +64,6 @@ def run_visual_metrics(config, jobs):
                 'extract': True
             }]
 
-            # Set the artifact prefix for the browsertime results
-            job.setdefault('attributes', {})
-            job['attributes']['artifact_prefix'] = 'public/test_info'
-
             # vismet runs on Linux but we want to have it displayed
             # alongside the job it was triggered by to make it easier for
             # people to find it back.