### 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)

import math
import re
import sys
import traceback
import warnings
from bisect import insort_left
from collections import defaultdict
from datetime import datetime, timedelta
from functools import wraps
from json import JSONDecodeError
from operator import itemgetter
from typing import Any, Callable, Collection, Iterator, Mapping, MutableMapping, Sequence
from urllib.parse import unquote, urljoin, urlsplit
import configupdater
import flask.json
import lazy_object_proxy
import markupsafe
import nvd3
import sqlalchemy as sqla
from croniter import croniter
from flask import (
    Response,
    abort,
    before_render_template,
    flash,
    g,
    make_response,
    redirect,
    render_template,
    request,