**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
self.start_date = timezone.utcnow()
            if self.state == State.UP_FOR_RESCHEDULE:
                task_reschedule: TR = TR.query_for_task_instance(self, session=session).first()
                if task_reschedule:
                    self.start_date = task_reschedule.start_date
            
            
            
            dep_context = DepContext(
                deps=REQUEUEABLE_DEPS,
                ignore_all_deps=ignore_all_deps,
                ignore_depends_on_past=ignore_depends_on_past,
                ignore_task_deps=ignore_task_deps,
                ignore_ti_state=ignore_ti_state,
            )
            if not self.are_dependencies_met(dep_context=dep_context, session=session, verbose=True):
                self.state = State.NONE
                self.log.warning(hr_line_break)
                self.log.warning(
                    "Rescheduling due to concurrency limits reached "
                    "at task runtime. Attempt %s of "
                    "%s. State set to NONE.",
                    self.try_number,
                    self.max_tries + 1,
                )
                self.log.warning(hr_line_break)
                self.queued_dttm = timezone.utcnow()
                session.merge(self)
                session.commit()
                return False