### 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)

#
#
from __future__ import annotations
from unittest import mock
from unittest.mock import mock_open, patch
import pytest
from hvac.exceptions import InvalidPath, VaultError
from airflow.providers.hashicorp._internal_client.vault_client import _VaultClient
class TestVaultClient:
    @mock.patch("airflow.providers.hashicorp._internal_client.vault_client.hvac")
    def test_version_wrong(self, mock_hvac):
        mock_client = mock.MagicMock()
        mock_hvac.Client.return_value = mock_client
        with pytest.raises(VaultError, match="The version is not supported: 4"):
            _VaultClient(auth_type="approle", kv_engine_version=4)
    @mock.patch("airflow.providers.hashicorp._internal_client.vault_client.hvac")
    def test_custom_mount_point(self, mock_hvac):
        mock_client = mock.MagicMock()
        mock_hvac.Client.return_value = mock_client
        vault_client = _VaultClient(auth_type="userpass", mount_point="custom")
        assert "custom" == vault_client.mount_point
    @mock.patch("airflow.providers.hashicorp._internal_client.vault_client.hvac")
    def test_version_one_init(self, mock_hvac):
        mock_client = mock.MagicMock()
        mock_hvac.Client.return_value = mock_client
        vault_client = _VaultClient(auth_type="userpass", kv_engine_version=1)
        assert 1 == vault_client.kv_engine_version
    @mock.patch("airflow.providers.hashicorp._internal_client.vault_client.hvac")
    def test_approle(self, mock_hvac):