### Apache Airflow version

2.5.1

### What happened

/calendar page give a problem, here is the capture



![屏幕截图 2023-01-30 093116](https://user-images.githubusercontent.com/19165258/215369479-9fc7de5c-f190-460c-9cf7-9ab27d8ac355.png)


### What you think should happen instead

_No response_

### How to reproduce

_No response_

### Operating System

Ubuntu 22.04.1 LTS

### Versions of Apache Airflow Providers

Distributor ID: Ubuntu
Description:    Ubuntu 22.04.1 LTS
Release:        22.04
Codename:       jammy

### Deployment

Other

### Deployment details


Distributor ID: Ubuntu
Description:    Ubuntu 22.04.1 LTS
Release:        22.04
Codename:       jammy

### Anything else

_No response_

### Are you willing to submit PR?

- [ ] 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)

if robots_file_access_count > 0:
                flash(
                    Markup(
                        "Recent requests have been made to /robots.txt. "
                        "This indicates that this deployment may be accessible to the public internet. "
                        "This warning can be disabled by setting webserver.warn_deployment_exposure=False in "
                        "airflow.cfg. Read more about web deployment security <a href="
                        f'"{get_docs_url("security/webserver.html")}">'
                        "here</a>"
                    ),
                    "warning",
                )
        return self.render_template(
            "airflow/dags.html",
            dags=dags,
            dashboard_alerts=dashboard_alerts,
            migration_moved_data_alerts=sorted(set(_iter_parsed_moved_data_table_names())),
            current_page=current_page,
            search_query=arg_search_query if arg_search_query else "",
            page_title=Markup(page_title) if page_title_has_markup else page_title,
            page_size=dags_per_page,
            num_of_pages=num_of_pages,
            num_dag_from=min(start + 1, num_of_all_dags),
            num_dag_to=min(end, num_of_all_dags),
            num_of_all_dags=num_of_all_dags,
            paging=wwwutils.generate_pages(
                current_page,
                num_of_pages,
                search=escape(arg_search_query) if arg_search_query else None,
                status=arg_status_filter if arg_status_filter else None,