**Apache Airflow version**:

2.0.1

**What happened**:

When clearing task across dags using `ExternalTaskMarker` the dag state of the external `DagRun` is not set to active. So cleared tasks in the external dag will not automatically start if the `DagRun` is a Failed or Succeeded state.

**What you expected to happen**:

The external `DagRun` run should also be set to Running state.

**How to reproduce it**:

Clear tasks in an external dag using an ExternalTaskMarker.


**Anything else we need to know**:

Looking at the code is has:

https://github.com/apache/airflow/blob/b23fc137812f5eabf7834e07e032915e2a504c17/airflow/models/dag.py#L1323-L1335

It seems like it intentionally calls the dag member method `set_dag_run_state` instead of letting the helper function `clear_task_insntances` set the `DagRun` state. But the member method will only change the state of `DagRun`s of dag where the original task is, while I believe `clear_task_instances` would correctly change the state of all involved `DagRun`s.

airflow/models/taskinstance.py
"""Log URL for TaskInstance"""
        iso = quote(self.execution_date.isoformat())
        base_url = conf.get('webserver', 'BASE_URL')
        return base_url + f"/log?execution_date={iso}&task_id={self.task_id}&dag_id={self.dag_id}"
    @property
    def mark_success_url(self):
        """URL to mark TI success"""
        iso = quote(self.execution_date.isoformat())
        base_url = conf.get('webserver', 'BASE_URL')
        return base_url + (
            "/success"
            f"?task_id={self.task_id}"
            f"&dag_id={self.dag_id}"
            f"&execution_date={iso}"
            "&upstream=false"
            "&downstream=false"
        )
    @provide_session
    def current_state(self, session=None) -> str: