### Description

In Airflow UI. If we go to Browse --> DAG Runs, then DAG Runs view will be displayed.

Table contains a lot of insightful values likes DAG execution date, Start date, end date, Dag config etc

Request to add DAG duration column in the same table.
DAG Duration i.e. DAG end_date timestamp  - DAG start_date timestamp

### Use case/motivation

Analytics purpose of knowing DAG duration at all DAGs level. So that I can easily find out which DAG  have least and max duration.

### Related issues

Checked open issues. There aren't any

### Are you willing to submit a 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)

airflow/www/views.py
)
        if dag_run is None:
            flash(f"No DAG run found for DAG id {dag_id} and run id {run_id}", "error")
            return redirect(request.referrer or url_for('Airflow.index'))
        else:
            try:
                duration = dag_run.end_date - dag_run.start_date
            except TypeError:
                
                duration = None
            dagrun_attributes = [
                ("Logical date", wwwutils.datetime_html(dag_run.execution_date)),
                ("Queued at", wwwutils.datetime_html(dag_run.queued_at)),
                ("Start date", wwwutils.datetime_html(dag_run.start_date)),
                ("End date", wwwutils.datetime_html(dag_run.end_date)),
                ("Duration", str(duration)),
                ("Current state", wwwutils.state_token(dag_run.state)),
                ("Run type", dag_run.run_type),
                ("Externally triggered", dag_run.external_trigger),
                ("Config", wwwutils.json_render(dag_run.conf, lexers.JsonLexer)),
            ]
            return self.render_template(
                "airflow/dagrun_details.html",
                dag=dag,
                dag_id=dag_id,
                run_id=run_id,
                execution_date=dag_run.execution_date.isoformat(),
                dagrun_attributes=dagrun_attributes,
            )
    def _mark_task_instance_state(