RuntimeError: cannot schedule new futures after shutdown when using external Kubernetes cluster

**Describe the issue**:

Hi,

I'm encountering the following error when trying to run Dask jobs on an **external Kubernetes cluster**:

```
RuntimeError: cannot schedule new futures after shutdown
```

However, when I use a local Kubernetes cluster like `rancher-desktop`, everything works as expected without any RuntimeError.

I *suspect* that the issue might be related to the `getaddrinfo` call, which utilizes `ThreadPoolExecutor` for asynchronous operation. It seems that the default `ThreadPoolExecutor` might already be closed by the time it's called, leading to the error.

**Minimal Complete Verifiable Example**:

```python
from dask_kubernetes.operator import KubeCluster
import time
import random
import joblib

def square(x):
time.sleep(random.expovariate(1.5))
return x**2

def main():
cluster = KubeCluster(
name="my-dask-cluster",
image="ghcr.io/dask/dask:2023.3.2-py3.11",
env={"EXTRA_PIP_PACKAGES": "joblib"},
)
print("Cluster created")
cluster.scale(1)
client = cluster.get_client()
print("Client", client)
joblib.parallel_backend(
"dask", client=client, pure=False, wait_for_workers_timeout=60
)

results = joblib.Parallel(n_jobs=2)(
joblib.delayed(square)(arg) for arg in range(10)
)
print(results)

if __name__ == "__main__":
main()

```

This results in

```
$ python k8s_cluster.py
╭─────────────────── Creating KubeCluster 'my-dask-cluster' ───────────────────╮
│ │
│ DaskCluster Running │
│ Scheduler Pod Running │
│ Scheduler Service Created │
│ Default Worker Group Created │
│ │
│ ⠏ Getting dashboard URL │
╰──────────────────────────────────────────────────────────────────────────────╯
Cluster created
/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/distributed/client.py:1381: VersionMismatchWarning: Mismatched versions found

+-------------+----------------+----------------+---------+
| Package | Client | Scheduler | Workers |
+-------------+----------------+----------------+---------+
| distributed | 2023.3.2.1 | 2023.3.2 | None |
| lz4 | None | 4.3.2 | None |
| python | 3.11.3.final.0 | 3.11.0.final.0 | None |
+-------------+----------------+----------------+---------+
warnings.warn(version_module.VersionMismatchWarning(msg[0]["warning"]))
Client
[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
Exception ignored in atexit callback:
Traceback (most recent call last):
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/dask_kubernetes/operator/kubecluster/kubecluster.py", line 1056, in reap_clusters
asyncio.run(_reap_clusters())
File "/opt/homebrew/Cellar/python@3.11/3.11.3/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/runners.py", line 190, in run
return runner.run(main)
^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/python@3.11/3.11.3/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/runners.py", line 118, in run
return self._loop.run_until_complete(task)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/python@3.11/3.11.3/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 653, in run_until_complete
return future.result()
^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/dask_kubernetes/operator/kubecluster/kubecluster.py", line 1054, in _reap_clusters
cluster.close(timeout=10)
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/dask_kubernetes/operator/kubecluster/kubecluster.py", line 702, in close
return self.sync(self._close, timeout=timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/distributed/utils.py", line 349, in sync
return sync(
^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/distributed/utils.py", line 416, in sync
raise exc.with_traceback(tb)
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/distributed/utils.py", line 389, in f
result = yield future
^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/tornado/gen.py", line 769, in run
value = future.result()
^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/dask_kubernetes/operator/kubecluster/kubecluster.py", line 710, in _close
await custom_objects_api.delete_namespaced_custom_object(
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/kubernetes_asyncio/client/api_client.py", line 185, in __call_api
response_data = await self.request(
^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/kubernetes_asyncio/client/rest.py", line 220, in DELETE
return (await self.request("DELETE", url,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/kubernetes_asyncio/client/rest.py", line 177, in request
r = await self.pool_manager.request(**args)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/aiohttp/client.py", line 536, in _request
conn = await self._connector.connect(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/aiohttp/connector.py", line 540, in connect
proto = await self._create_connection(req, traces, timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/aiohttp/connector.py", line 901, in _create_connection
_, proto = await self._create_direct_connection(req, traces, timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/aiohttp/connector.py", line 1152, in _create_direct_connection
hosts = await asyncio.shield(host_resolved)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/aiohttp/connector.py", line 874, in _resolve_host
addrs = await self._resolver.resolve(host, port, family=self._family)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/Artimi/playground/dask/.venv/lib/python3.11/site-packages/aiohttp/resolver.py", line 33, in resolve
infos = await self._loop.getaddrinfo(
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/python@3.11/3.11.3/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 867, in getaddrinfo
return await self.run_in_executor(
^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/python@3.11/3.11.3/Frameworks/Python.framework/Versions/3.11/lib/python3.11/asyncio/base_events.py", line 829, in run_in_executor
executor.submit(func, *args), loop=self)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/opt/homebrew/Cellar/python@3.11/3.11.3/Frameworks/Python.framework/Versions/3.11/lib/python3.11/concurrent/futures/thread.py", line 167, in submit
raise RuntimeError('cannot schedule new futures after shutdown')
RuntimeError: cannot schedule new futures after shutdown

```

**Anything else we need to know?**:

**Environment**:

- Dask version: 2023.3.2
- Python version: 3.11
- Operating System: MacOS - host, ghcr.io/dask/dask:2023.3.2-py3.11 - image
- Install method (conda, pip, source): pip