### Apache Airflow version

2.4.2

### What happened

Create a DAG and set the schedule parameter using a CronTriggerTimeTable instance. Enable the DAG so that there is DAG run data. Try to access the Calendar View for the DAG. An ERR_EMPTY_RESPONSE error is displayed instead of the page.

The Calendar View is accessible for other DAGs  that are using the schedule_interval set to a cron string instead.

### What you think should happen instead

The Calendar View should have been displayed.

### How to reproduce

Create a DAG and set the schedule parameter to a CronTriggerTimeTable instance. Enable the DAG and allow some DAG runs to occur. Try to access the Calender View for the DAG.

### Operating System

Red Hat Enterprise Linux 8.6

### Versions of Apache Airflow Providers

_No response_

### Deployment

Virtualenv installation

### Deployment details

Airflow 2.4.2 installed via pip with Python3.9 to venv using constraints.

### Anything else

_No response_

### Are you willing to submit PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

return self._set_notification_property(items, "email_sent", True)
    @action(
        "mulemailsentfalse",
        "Set email sent to false",
        "Are you sure you want to mark these SLA alerts as emails not sent yet?",
        single=False,
    )
    def action_mulemailsentfalse(self, items: list[SlaMiss]):
        return self._set_notification_property(items, "email_sent", False)
    @provide_session
    def _set_notification_property(self, items: list[SlaMiss], attr: str, new_value: bool, session=None):
        try:
            count = 0
            for sla in items:
                count += 1
                setattr(sla, attr, new_value)
                session.merge(sla)
            session.commit()
            flash(f"{count} SLAMisses had {attr} set to {new_value}.")
        except Exception as ex:
            flash(str(ex), "error")
            flash("Failed to set state", "error")
        self.update_redirect()
        return redirect(self.get_default_url())