### Apache Airflow version

2.6.3

### What happened

Select tasks from List Task Instance page in UI and select clear
Only those tasks are cleared and downsteam tasks are not also cleared as they are in the DAG graph view

### What you think should happen instead

downstream tasks should also be cleared

### How to reproduce

Select tasks from List Task Instance page in UI for which there are downstream tasks and select clear

### Operating System

rocky

### Versions of Apache Airflow Providers

_No response_

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### 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)

"""Deletes DAG."""
        from airflow.api.common import delete_dag
        from airflow.exceptions import DagNotFound
        dag_id = request.values.get("dag_id")
        origin = get_safe_url(request.values.get("origin"))
        redirect_url = get_safe_url(request.values.get("redirect_url"))
        try:
            delete_dag.delete_dag(dag_id)
        except DagNotFound:
            flash(f"DAG with id {dag_id} not found. Cannot delete", "error")
            return redirect(redirect_url)
        except AirflowException:
            flash(
                f"Cannot delete DAG with id {dag_id} because some task instances of the DAG "
                "are still running. Please mark the  task instances as "
                "failed/succeeded before deleting the DAG",
                "error",
            )
            return redirect(redirect_url)
        flash(f"Deleting DAG with id {dag_id}. May take a couple minutes to fully disappear.")
        
        return redirect(origin)
    @expose("/dags/<string:dag_id>/trigger", methods=["POST", "GET"])
    @auth.has_access(
        [
            (permissions.ACTION_CAN_EDIT, permissions.RESOURCE_DAG),