### Description

Auto-refresh is an awesome new feature! Right now it occurs every [3 seconds](https://github.com/apache/airflow/blob/79d85573591f641db4b5f89a12213e799ec6dea1/airflow/www/static/js/tree.js#L463), and this interval is not configurable. Making this interval configurable would be useful.

### Use case/motivation

On a DAG with many tasks and many active DAG runs, auto-refresh can be a significant strain on the webserver. We observed our production webserver reach 100% CPU today when we had about 30 running DAG runs of a DAG containing about 50 tasks. Being able to increase the interval to guard against this would be helpful.

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] 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
dag = dag.partial_subset(task_ids_or_regex=root, include_downstream=False, include_upstream=True)
        num_runs = request.args.get('num_runs', type=int)
        if num_runs is None:
            num_runs = conf.getint('webserver', 'default_dag_run_display_number')
        try:
            base_date = timezone.parse(request.args["base_date"])
        except (KeyError, ValueError):
            base_date = dag.get_latest_execution_date() or timezone.utcnow()
        with create_session() as session:
            dag_runs = (
                session.query(DagRun)
                .filter(DagRun.dag_id == dag.dag_id, DagRun.execution_date <= base_date)
                .order_by(DagRun.execution_date.desc())
                .limit(num_runs)
                .all()
            )
            dag_runs = {dr.execution_date: alchemy_to_dict(dr) for dr in dag_runs}
            tree_data = self._get_tree_data(dag_runs, dag, base_date, session=session)
        
        return htmlsafe_json_dumps(tree_data, separators=(',', ':'))
    @expose('/robots.txt')
    @action_logging
    def robots(self):
        """
        Returns a robots.txt file for blocking certain search engine crawlers. This mitigates some
        of the risk associated with exposing Airflow to the public internet, however it does not
        address the real security risks associated with such a deployment.
        """
        return send_from_directory(current_app.static_folder, 'robots.txt')
class ConfigurationView(AirflowBaseView):