**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/dag.py
elif run_type and execution_date:
            if not isinstance(run_type, DagRunType):
                raise ValueError(f"`run_type` expected to be a DagRunType is {type(run_type)}")
            run_id = DagRun.generate_run_id(run_type, execution_date)
        elif not run_id:
            raise AirflowException(
                "Creating DagRun needs either `run_id` or both `run_type` and `execution_date`"
            )
        run = DagRun(
            dag_id=self.dag_id,
            run_id=run_id,
            execution_date=execution_date,
            start_date=start_date,
            external_trigger=external_trigger,
            conf=conf,
            state=state,
            run_type=run_type,
            dag_hash=dag_hash,
            creating_job_id=creating_job_id,
        )
        session.add(run)
        session.flush()
        run.dag = self
        
        
        run.verify_integrity(session=session)
        return run
    @classmethod
    @provide_session
    def bulk_sync_to_db(cls, dags: Collection["DAG"], session=None):