### Apache Airflow version

2.6.1

### What happened

Trying to connect to Vault using `auth_type` = `aws_iam`. I am receiving the following error: `AttributeError: 'Client' has no attribute 'auth_aws_iam'`. Looking through [the code](https://github.com/apache/airflow/blob/main/airflow/providers/hashicorp/_internal_client/vault_client.py#L303), you are using `client.auth_aws_iam`, but the [HVAC docs](https://hvac.readthedocs.io/en/stable/usage/auth_methods/aws.html#caveats-for-non-default-aws-regions) use `client.auth.aws.iam_login`. You should also add support for `boto3.Session()` to use role based access.

### What you think should happen instead

Airflow should authenticate to Vault using AWS auth.

### How to reproduce

Setup a secrets backend of `airflow.providers.hashicorp.secrets.vault.VaultBackend` and set `auth_type` = `aws_iam`. It will error out saying that the client doesn't have an attribute named `auth_aws_iam`.

### Operating System

Docker

### Versions of Apache Airflow Providers

_No response_

### Deployment

Official Apache Airflow Helm Chart

### Deployment details

_No response_

### 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)

mock_client = mock.MagicMock()
        mock_hvac.Client.return_value = mock_client
        mock_client.secrets.kv.v2.read_secret_version.return_value = {
            "request_id": "94011e25-f8dc-ec29-221b-1f9c1d9ad2ae",
            "lease_id": "",
            "renewable": False,
            "lease_duration": 0,
            "data": {
                "data": {"secret_key": "secret_value"},
                "metadata": {
                    "created_time": "2020-03-16T21:01:43.331126Z",
                    "deletion_time": "",
                    "destroyed": False,
                    "version": 1,
                },
            },
            "wrap_info": None,
            "warnings": None,
            "auth": None,
        }
        vault_client = _VaultClient(