**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
partial_dag = self.task.dag.partial_subset(
                    self.task.downstream_task_ids,
                    include_downstream=False,
                    include_upstream=False,
                    include_direct_upstream=True,
                )
                dag_run.dag = partial_dag
                info = dag_run.task_instance_scheduling_decisions(session)
                skippable_task_ids = {
                    task_id
                    for task_id in partial_dag.task_ids
                    if task_id not in self.task.downstream_task_ids
                }
                schedulable_tis = [ti for ti in info.schedulable_tis if ti.task_id not in skippable_task_ids]
                for schedulable_ti in schedulable_tis:
                    if not hasattr(schedulable_ti, "task"):
                        schedulable_ti.task = self.task.dag.get_task(schedulable_ti.task_id)
                num = dag_run.schedule_tis(schedulable_tis)
                self.log.info("%d downstream tasks scheduled from follow-on schedule check", num)
                session.commit()
            except OperationalError as e:
                
                self.log.info(
                    f"Skipping mini scheduling run due to exception: {e.statement}",
                    exc_info=True,
                )
                session.rollback()
    def _prepare_and_execute_task_with_callbacks(self, context, task):