SFTP Teardown failure

When collecting logs it looks like the instance teardown path recently (within the last month) started throwing an unhandled exception in the failure path. I see the following traceback in cloud-init integration tests on failure.

```python
--- Logging error ---
Traceback (most recent call last):
File "/usr/lib/python3.12/logging/__init__.py", line 1163, in emit
stream.write(msg + self.terminator)
ValueError: I/O operation on closed file.
Call stack:
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/pycloudlib/instance.py", line 204, in __del__
self._sftp_client.close()
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp_client.py", line 194, in close
self._log(INFO, "sftp session closed.")
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp_client.py", line 182, in _log
super()._log(
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp.py", line 169, in _log
self.logger.log(level, msg, *args)
Message: '[chan %s] sftp session closed.'
Arguments: ('8',)
--- Logging error ---
Traceback (most recent call last):
File "/usr/lib/python3.12/logging/__init__.py", line 1163, in emit
stream.write(msg + self.terminator)
ValueError: I/O operation on closed file.
Call stack:
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp_client.py", line 194, in close
self._log(INFO, "sftp session closed.")
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp_client.py", line 182, in _log
super()._log(
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp.py", line 169, in _log
self.logger.log(level, msg, *args)
Message: '[chan %s] sftp session closed.'
Arguments: ('11',)
--- Logging error ---
Traceback (most recent call last):
File "/usr/lib/python3.12/logging/__init__.py", line 1163, in emit
stream.write(msg + self.terminator)
ValueError: I/O operation on closed file.
Call stack:
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/pycloudlib/instance.py", line 204, in __del__
self._sftp_client.close()
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp_client.py", line 194, in close
self._log(INFO, "sftp session closed.")
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp_client.py", line 182, in _log
super()._log(
File "/home/runner/work/cloud-init/cloud-init/.tox/integration-tests-ci/lib/python3.12/site-packages/paramiko/sftp.py", line 169, in _log
self.logger.log(level, msg, *args)
Message: '[chan %s] sftp session closed.'
Arguments: ('9',)
```