### 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
self,
        dag_runs: Iterable[DagRun],
        dag: DAG,
        base_date: DateTime,
        session: settings.Session,
    ):
        """Returns formatted dag_runs for Tree view"""
        dates = sorted(dag_runs.keys())
        min_date = min(dag_runs, default=None)
        task_instances = {
            (ti.task_id, ti.execution_date): ti
            for ti in dag.get_task_instances(start_date=min_date, end_date=base_date, session=session)
        }
        expanded = set()
        
        
        
        node_count = 0
        node_limit = 5000 / max(1, len(dag.leaves))
        def encode_ti(task_instance: Optional[models.TaskInstance]) -> Optional[List]: