### What do you see as an issue?

Hello!

I don't know if this is intended, but `default_args` is not an override when using nested TaskGroups.

```python
def callback_in_dag(context: Context):
    print("DAG!")

def callback_in_task_group(context: Context):
    print("Parent TaskGroup!")

with DAG(
    "some_dag_id",
    default_args={
        "on_failure_callback": callback_in_dag
    },
    schedule=None,
    start_date=datetime(2023, 1, 1)
) as dag:
    with TaskGroup(
        "parent_tg", 
        default_args={
            "on_failure_callback": callback_in_task_group
        }
    ) as parent_tg:
        with TaskGroup("child_tg") as child_tg:
            BashOperator(task_id="task_1", bash_command="nooooo_command")
```

I want the result to be "Parent TaskGroup!", but I get "DAG!".

```
[2023-05-30, 10:38:52 KST] {logging_mixin.py:137} INFO - DAG!
```

### Solving the problem

Add `_update_default_args` like [link](https://github.com/apache/airflow/blob/f6bb4746efbc6a94fa17b6c77b31d9fb17305ffc/airflow/models/baseoperator.py#L139)

#### [airflow/utils/task_group.py](https://github.com/apache/airflow/blob/main/airflow/utils/task_group.py)
```python
...
class TaskGroup(DAGNode):
    def __init__(...):
        ...
        self.default_args = copy.deepcopy(default_args or {})

        # Call 'self._update_default_args' when exists parent_group
        if parent_group is not None:
            self._update_default_args(parent_group)
        ...
    ...
    # Update self.default_args
    def _update_default_args(parent_group: TaskGroup):
        if parent_group.default_args:
            self.default_args.update(parent_group.default_args) 
...
```

### 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)

with DAG("test_dag", start_date=pendulum.parse("20200101")):
        tg = TaskGroup("section")
        task = EmptyOperator(task_id="task")
        with pytest.raises(TaskAlreadyInTaskGroup) as ctx:
            tg.add(task)
    assert str(ctx.value) == "cannot add 'task' to 'section' (already in the DAG's root group)"
def test_add_to_another_group():
    with DAG("test_dag", start_date=pendulum.parse("20200101")):
        tg = TaskGroup("section_1")
        with TaskGroup("section_2"):
            task = EmptyOperator(task_id="task")
        with pytest.raises(TaskAlreadyInTaskGroup) as ctx:
            tg.add(task)
    assert str(ctx.value) == "cannot add 'section_2.task' to 'section_1' (already in group 'section_2')"
def test_task_group_edge_modifier_chain():