### Body

Currently `start_date` is mandatory parameter.
For DAGs with `schedule=None` we can relax this requirement as no scheduling calculation needed so the `start_date` parameter isn't used.

### Committer

- [X] I acknowledge that I am a maintainer/committer of the Apache Airflow project.
"""
        We should never create dagruns for unpaused DAGs
        """
        dag = DAG(dag_id="test_dags", start_date=DEFAULT_DATE)
        EmptyOperator(task_id="dummy", dag=dag, owner="airflow")
        session = settings.Session()
        orm_dag = DagModel(
            dag_id=dag.dag_id,
            has_task_concurrency_limits=False,
            next_dagrun=DEFAULT_DATE,
            next_dagrun_create_after=DEFAULT_DATE + timedelta(days=1),
            is_active=True,
        )
        session.add(orm_dag)
        session.flush()
        query, _ = DagModel.dags_needing_dagruns(session)
        needed = query.all()
        assert needed == [orm_dag]
        orm_dag.is_paused = True
        session.flush()
        query, _ = DagModel.dags_needing_dagruns(session)
        dag_models = query.all()
        assert dag_models == []
        session.rollback()
        session.close()
    def test_dags_needing_dagruns_doesnot_send_dagmodel_with_import_errors(self, session):