**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
"""
    Simplified Task Instance.
    Used to send data between processes via Queues.
    """
    def __init__(self, ti: TaskInstance):
        self._dag_id: str = ti.dag_id
        self._task_id: str = ti.task_id
        self._execution_date: datetime = ti.execution_date
        self._start_date: datetime = ti.start_date
        self._end_date: datetime = ti.end_date
        self._try_number: int = ti.try_number
        self._state: str = ti.state
        self._executor_config: Any = ti.executor_config
        self._run_as_user: Optional[str] = None
        if hasattr(ti, 'run_as_user'):
            self._run_as_user = ti.run_as_user
        self._pool: str = ti.pool
        self._priority_weight: Optional[int] = None
        if hasattr(ti, 'priority_weight'):
            self._priority_weight = ti.priority_weight
        self._queue: str = ti.queue
        self._key = ti.key
    
    @property
    def dag_id(self) -> str:
        return self._dag_id
    @property
    def task_id(self) -> str: