### Description

Hi! 

I think it would be useful to have a helm chart parameter that (if set) will allow to overwrite DAGs mount path in airflow containers. Mount path is already defined in `airflow_dags_mount` [here](https://github.com/apache/airflow/blob/main/chart/templates/_helpers.yaml#L475) , but currently mountPath is hardcoded to `{{ printf "%s/dags" .Values.airflowHome }}`.

### Use case/motivation

Setting this new mount path to a subfolder `/dags_folder/dags_recieved_from_git` will make it possible to:

* Add some rarely changing DAGs during image building to your `dags_folder` instead of receiving them from git.
* mount to your DAGs folder custom configmaps (for example, to `/dags_folder/my_custom_configmap`).

Let's say your `dags_folder` is `/opt/airflow/dags`. In this case overall it will look like:
```
/opt/airflow/
└── dags
    ├── dags_recieved_from_git
    │   ├── my_frequently_changing_dag_1.py  # Synced from git repo
    │   └── my_frequently_changing_dag_2.py  # Synced from git repo
    ├── my_custom_configmap
    │   └── configmap_data.txt  # Mounted from K8s config map
    ├── my_rarely_changing_dag_1.py  # Added during image build process
    └── my_rarely_changing_dag_2.py  # Added during image build process
```

It was just an example and I think there might be other use cases for this parameter.

### Related issues

_No response_

### Are you willing to submit a 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)

docs = render_chart(
            values={
                "executor": "CeleryExecutor",
            },
            show_only=["templates/configmaps/configmap.yaml"],
        )
        expected = "flower_url_prefix = "
        cfg = jmespath.search('data."airflow.cfg"', docs[0])
        assert expected in cfg.splitlines()
    def test_overridedn_flower_url_prefix(self):
        docs = render_chart(
            values={"executor": "CeleryExecutor", "ingress": {"flower": {"path": "/overridden-path"}}},
            show_only=["templates/configmaps/configmap.yaml"],
        )
        expected = "flower_url_prefix = /overridden-path"
        cfg = jmespath.search('data."airflow.cfg"', docs[0])
        assert expected in cfg.splitlines()