Fixup elastic-agent docker image

Author: tobio

.github/workflows/copilot-setup-steps.yml

@@ -60,7 +60,7 @@ jobs:
           - 5601:5601
         options: --health-cmd="curl http://localhost:5601/api/status" --health-interval=10s --health-timeout=5s --health-retries=10
       fleet:
-        image: docker.elastic.co/beats/elastic-agent:9.0.3
+        image: docker.elastic.co/elastic-agent/elastic-agent:9.0.3
         env:
           SERVER_NAME: fleet
           FLEET_ENROLL: "1"