### 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
last_task_instance_query_result, running_task_instance_query_result
            ).alias('final_ti')
        else:
            final_task_instance_query_result = running_task_instance_query_result.subquery('final_ti')
        qry = session.query(
            final_task_instance_query_result.c.dag_id,
            final_task_instance_query_result.c.state,
            sqla.func.count(),
        ).group_by(final_task_instance_query_result.c.dag_id, final_task_instance_query_result.c.state)
        data = {}
        for dag_id, state, count in qry:
            if dag_id not in data:
                data[dag_id] = {}
            data[dag_id][state] = count
        payload = {}
        for dag_id in filter_dag_ids:
            payload[dag_id] = []
            for state in State.task_states:
                count = data.get(dag_id, {}).get(state, 0)
                payload[dag_id].append({'state': state, 'count': count})
        return wwwutils.json_response(payload)
    @expose('/last_dagruns', methods=['POST'])
    @auth.has_access(
        [
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_DAG),
            (permissions.ACTION_CAN_READ, permissions.RESOURCE_DAG_RUN),
        ]
    )
    @provide_session
    def last_dagruns(self, session=None):