### Apache Airflow version

2.4.2

### What happened

In the scenario where we have 2 dags, 1 dag dependent on the other by having an ExternalTaskMarker on the parent dag pointing to the child dag and we have some number of mapped tasks in the child dag that have been expanded (map_index is not -1). 
If we were to clear the parent dag, the child dag's mapped tasks will NOT be cleared. It will not appear in the "Task instances to be cleared" list

### What you think should happen instead

I believe the behaviour should be having the child dag's mapped tasks cleared when the parent dag is cleared.

### How to reproduce

1. Create a parent dag with an ExternalTaskMarker
2. Create a child dag which has some ExternalTaskSensor that the ExternalTaskMarker is pointing to
3. Add any number of mapped tasks downstream of that ExternalTaskSensor
4. Clear the parent dag's ExternalTaskMarker (or any task upstream of it)

### Operating System

Mac OS Monterey 12.6

### 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?

- [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)

"""
        Triggers the appropriate callback depending on the value of success, namely the
        on_failure_callback or on_success_callback. This method gets the context of a
        single TaskInstance part of this DagRun and passes that to the callable along
        with a 'reason', primarily to differentiate DagRun failures.
        .. note: The logs end up in
            ``$AIRFLOW_HOME/logs/scheduler/latest/PROJECT/DAG_FILE.py.log``
        :param dagrun: DagRun object
        :param success: Flag to specify if failure or success callback should be called
        :param reason: Completion reason
        :param session: Database session
        """
        callback = self.on_success_callback if success else self.on_failure_callback
        if callback:
            self.log.info("Executing dag callback function: %s", callback)
            tis = dagrun.get_task_instances(session=session)
            ti = tis[-1]  
            ti.task = self.get_task(ti.task_id)
            context = ti.get_template_context(session=session)
            context.update({"reason": reason})
            try:
                callback(context)
            except Exception:
                self.log.exception("failed to invoke dag state update callback")
                Stats.incr("dag.callback_exceptions")
    def get_active_runs(self):