### Description

Support mounting to multiple namespaces with the Hashicorp Vault Secrets Back-end

### Use case/motivation

As a data engineer I wish to utilize secrets stored in multiple mount paths (to support connecting to multiple namespaces)  without having to mount to a higher up namespace.

### Related issues

_No response_

### Are you willing to submit a 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)

"""
    Retrieves Authenticated client from Hashicorp Vault. This is purely internal class promoting
    authentication code reuse between the Hook and the SecretBackend, it should not be used directly in
    Airflow DAGs. Use VaultBackend for backend integration and Hook in case you want to communicate
    with VaultHook using standard Airflow Connection definition.
    :param url: Base URL for the Vault instance being addressed.
    :param auth_type: Authentication Type for Vault. Default is ``token``. Available values are in
        ('approle', 'aws_iam', 'azure', 'github', 'gcp', 'kubernetes', 'ldap', 'radius', 'token', 'userpass')
    :param auth_mount_point: It can be used to define mount_point for authentication chosen
          Default depends on the authentication method used.
    :param mount_point: The "path" the secret engine was mounted on. Default is "secret". Note that
         this mount_point is not used for authentication if authentication is done via a
         different engine. For authentication mount_points see, auth_mount_point.
    :param kv_engine_version: Selects the version of the engine to run (``1`` or ``2``, default: ``2``).
    :param token: Authentication token to include in requests sent to Vault
        (for ``token`` and ``github`` auth_type).
    :param token_path: path to file containing authentication token to include in requests sent to Vault
        (for ``token`` and ``github`` auth_type).
    :param username: Username for Authentication (for ``ldap`` and ``userpass`` auth_types).
    :param password: Password for Authentication (for ``ldap`` and ``userpass`` auth_types).
    :param key_id: Key ID for Authentication (for ``aws_iam`` and ''azure`` auth_type).
    :param secret_id: Secret ID for Authentication (for ``approle``, ``aws_iam`` and ``azure`` auth_types).
    :param role_id: Role ID for Authentication (for ``approle``, ``aws_iam`` auth_types).
    :param kubernetes_role: Role for Authentication (for ``kubernetes`` auth_type).
    :param kubernetes_jwt_path: Path for kubernetes jwt token (for ``kubernetes`` auth_type, default:
        ``/var/run/secrets/kubernetes.io/serviceaccount/token``).
    :param gcp_key_path: Path to Google Cloud Service Account key file (JSON)  (for ``gcp`` auth_type).
           Mutually exclusive with gcp_keyfile_dict
    :param gcp_keyfile_dict: Dictionary of keyfile parameters. (for ``gcp`` auth_type).
           Mutually exclusive with gcp_key_path