fix: correct E2E traces-list expected endpoint to /artist-consumer

The trace originates at the consumer (trigger sends POST to
/artist-consumer), so the trace's entry endpoint is /artist-consumer,
not /artist-provider. The previous expected data was incorrect —
it passed intermittently when the OAP happened to return
/artist-provider first.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: wu-sheng

tests/e2e/case/expected/traces-list.yml

@@ -19,7 +19,7 @@ traces:
   - segmentid: {{ notEmpty .segmentid }}
     endpointnames:
     {{- contains .endpointnames }}
-      - {{ notEmpty (index .endpointnames 0) }}
+      - /artist-consumer
     {{- end }}
     duration: {{ ge .duration 0 }}
     start: {{ notEmpty .start}}