Metric dag.<dag_id>.<task_id>.duration is missing

### Apache Airflow version Other Airflow 3 version (please specify below) ### If "Other Airflow 3 version" selected, which one? 3.0.6 ### What happened? Metric dag.<dag_id>.<task_id>.duration is missing. Found that the metric was removed in this particular commit - https://github.com/apache/airflow/pull/50141/files#diff-f660147b2482fe9eb7c256a6e9b5c0d8c0623fc31beaf5048e476e9bd1b7823b Is this intended? ### What you think should happen instead? Metric dag.<dag_id>.<task_id>.duration should be available as per documentation. ### How to reproduce Scrape airflow metrics and look for dag.<dag_id>.<task_id>.duration metric. ### Operating System Debian GNU/Linux 12 (bookworm) ### Versions of Apache Airflow Providers apache-airflow-providers-celery==3.12.2 apache-airflow-providers-cncf-kubernetes==10.8.2 apache-airflow-providers-common-compat==1.7.3 apache-airflow-providers-common-io==1.6.2 apache-airflow-providers-common-sql==1.27.5 apache-airflow-providers-fab==2.4.1 apache-airflow-providers-ftp==3.13.2 apache-airflow-providers-http==5.3.3 apache-airflow-providers-imap==3.9.2 apache-airflow-providers-postgres==6.2.3 apache-airflow-providers-smtp==2.2.0 apache-airflow-providers-sqlite==4.1.2 apache-airflow-providers-standard==1.6.0 ### Deployment Other ### Deployment details We use a slightly modified airflow helm chart ### Anything else? _No response_ ### Are you willing to submit PR? - [ ] Yes I am willing to submit a PR! ### Code of Conduct - [x] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)