**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
)
                else:
                    tis = tis.filter(TaskInstance.state.in_(state))
        tis = tis.order_by(TaskInstance.execution_date).all()
        return tis
    @property
    def roots(self) -> List[BaseOperator]:
        """Return nodes with no parents. These are first to execute and are called roots or root nodes."""
        return [task for task in self.tasks if not task.upstream_list]
    @property
    def leaves(self) -> List[BaseOperator]:
        """Return nodes with no children. These are last to execute and are called leaves or leaf nodes."""
        return [task for task in self.tasks if not task.downstream_list]
    def topological_sort(self, include_subdag_tasks: bool = False):
        """
        Sorts tasks in topographical order, such that a task comes after any of its
        upstream dependencies.
        Heavily inspired by:
        http://blog.jupo.org/2012/04/06/topological-sorting-acyclic-directed-graphs/
        :param include_subdag_tasks: whether to include tasks in subdags, default to False
        :return: list of tasks in topological order
        """
        from airflow.operators.subdag import SubDagOperator  
        
        graph_unsorted = OrderedDict((task.task_id, task) for task in self.tasks)
        graph_sorted = []  
        
        if len(self.tasks) == 0:
            return tuple(graph_sorted)