**Description**

For a DAG that looks like this:

```
A >> B
```

If A fails, B goes into "upstream_failed" state. If a user then marks A "success", B will remain in "upstream_failed" state. It will not automatically start running. This scenario often happens if the failure of A is dealt with outside of Airflow and the user does not want Airflow to run A again. But he usually expect Airflow to run B after A is marked "success".

**Use case / motivation**

After A is marked "success", its downstream tasks B should be cleared automatically and get ready to be scheduled. To avoid changing this behaviour completely, there can be a toggle button next to "Success" that lets the user decide if he wants Airflow to automatically clear downstream tasks that are in "upstream_failed" state.
airflow/models/dag.py
return get_last_dagrun(
            self.dag_id, session=session, include_externally_triggered=include_externally_triggered
        )
    @provide_session
    def has_dag_runs(self, session=None, include_externally_triggered=True) -> bool:
        return (
            get_last_dagrun(
                self.dag_id, session=session, include_externally_triggered=include_externally_triggered
            )
            is not None
        )
    @property
    def dag_id(self) -> str:
        return self._dag_id
    @dag_id.setter
    def dag_id(self, value: str) -> None:
        self._dag_id = value
    @property
    def full_filepath(self) -> str:
        return self._full_filepath
    @full_filepath.setter
    def full_filepath(self, value) -> None:
        self._full_filepath = value
    @property
    def concurrency(self) -> int:
        return self._concurrency
    @concurrency.setter
    def concurrency(self, value: int):