task.queued_duration metric not emitted in Airflow 3 (all executors)

### Under which category would you file this issue? Airflow Core ### Apache Airflow version 3.x ### What happened and how to reproduce it? What happened: task.queued_duration (legacy: dag.<dag_id>.<task_id>.queued_duration) is never emitted in Airflow 3 regardless of executor (LocalExecutor, CeleryExecutor, KubernetesExecutor). The companion metric task.scheduled_duration emits correctly. No `"cannot record queued_duration"` warnings appear in logs, the metric emission code is never reached, not silently skipped. How to reproduce: 1. Run any DAG on Airflow 3 with StatsD configured 2. Observe task.scheduled_duration (or legacy dag.<dag_id>.<task_id>.scheduled_duration) appears in metrics 3. Observe task.queued_duration (or legacy dag.<dag_id>.<task_id>.queued_duration) is absent ### What you think should happen instead? task.queued_duration should be emitted each time a task transitions from QUEUED --> RUNN…