### Apache Airflow version

2.2.2 (latest released)

### Operating System

MacOS 11.6.1

### Versions of Apache Airflow Providers

$ pip freeze | grep airflow
apache-airflow==2.2.2
apache-airflow-providers-celery==2.1.0
apache-airflow-providers-ftp==2.0.1
apache-airflow-providers-http==2.0.1
apache-airflow-providers-imap==2.0.1
apache-airflow-providers-sqlite==2.0.1

### Deployment

Other

### Deployment details

`airflow standalone`

### What happened

```
AttributeError: 'NoneType' object has no attribute 'update_relative'
```

### What you expected to happen

Task group should be set as downstream of `start` task, and upstream of `end` task

### How to reproduce

* Add the following code to dags folder

```python
from datetime import datetime

from airflow.decorators import dag, task, task_group


@dag(start_date=datetime(2023, 1, 1), schedule_interval="@once")
def test_dag_1():
    @task
    def start():
        pass

    @task
    def do_thing(x):
        print(x)

    @task_group
    def do_all_things():
        do_thing(1)
        do_thing(2)

    @task
    def end():
        pass

    start() >> do_all_things() >> end()


test_dag_1()
```

* Run `airflow standalone`

### 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)

tests/utils/test_task_group.py
{
                        'id': 'group_a.group_b',
                        'children': [
                            {'id': 'group_a.group_b.task2'},
                            {'id': 'group_a.group_b.task3'},
                            {'id': 'group_a.group_b.task4'},
                            {'id': 'group_a.group_b.downstream_join_id'},
                        ],
                    },
                    {'id': 'group_a.task5'},
                    {'id': 'group_a.upstream_join_id'},
                    {'id': 'group_a.downstream_join_id'},
                ],
            },
            {
                'id': 'group_c',
                'children': [
                    {'id': 'group_c.task6'},
                    {'id': 'group_c.task7'},
                    {'id': 'group_c.task8'},
                    {'id': 'group_c.upstream_join_id'},
                    {'id': 'group_c.downstream_join_id'},
                ],
            },
            {
                'id': 'group_d',
                'children': [
                    {'id': 'group_d.task11'},
                    {'id': 'group_d.task12'},
                    {'id': 'group_d.upstream_join_id'},