### Apache Airflow version

main (development)

### What happened

When creating a DAG with Task Groups and a Mapped Operator, if the Task Group is passed as argument to Mapped Operator's `partial` method it is ignored and the operator is not added to the group.

### What you think should happen instead

The Mapped Operator should be added to the Task Group passed as an argument.

### How to reproduce

Create a DAG with a source code like the following one

```python
from airflow import DAG
from airflow.operators.bash import BashOperator
from airflow.operators.empty import EmptyOperator
from airflow.utils import timezone
from airflow.utils.task_group import TaskGroup


with DAG("dag", start_date=timezone.datetime(2016, 1, 1)) as dag:
    start = EmptyOperator(task_id="start")
    finish = EmptyOperator(task_id="finish")

    group = TaskGroup("test-group")
    commands = ["echo a", "echo b", "echo c"]
    mapped = BashOperator.partial(task_id="task_2", task_group=group).expand(bash_command=commands)

    start >> group >> finish

# assert mapped.task_group == group

```

### Operating System

macOS 13.2.1 (22D68)

### Versions of Apache Airflow Providers

_No response_

### Deployment

Other

### Deployment details

_No response_

### 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)

TaskInstance.task_id == mapped.task_id,
            TaskInstance.run_id == dr.run_id,
        ).delete()
    for index in range(num_existing_tis):
        
        ti = TaskInstance(mapped, run_id=dr.run_id, map_index=index, state=TaskInstanceState.SUCCESS)
        session.add(ti)
    session.flush()
    mapped.expand_mapped_task(dr.run_id, session=session)
    indices = (
        session.query(TaskInstance.map_index, TaskInstance.state)
        .filter_by(task_id=mapped.task_id, dag_id=mapped.dag_id, run_id=dr.run_id)
        .order_by(TaskInstance.map_index)
        .all()
    )
    assert indices == expected
def test_expand_mapped_task_failed_state_in_db(dag_maker, session):
    """
    This test tries to recreate a faulty state in the database and checks if we can recover from it.
    The state that happens is that there exists mapped task instances and the unmapped task instance.
    So we have instances with map_index [-1, 0, 1]. The -1 task instances should be removed in this case.
    """
    literal = [1, 2]
    with dag_maker(session=session):
        task1 = BaseOperator(task_id="op1")
        mapped = MockOperator.partial(task_id="task_2").expand(arg2=task1.output)
    dr = dag_maker.create_dagrun()
    session.add(
        TaskMap(
            dag_id=dr.dag_id,