RuntimeError when generating cloud init config for Packer (GCPCluster)

**Describe the issue**:

I'm trying to build a custom OS image for my GCP cluster with packer. I'm using these steps: https://cloudprovider.dask.org/en/latest/packer.html

The util `get_cloud_init()` fails, seemingly on some underlying async logic.

**Minimal Complete Verifiable Example**:

```python
from dask_cloudprovider.gcp import GCPCluster

if __name__ == '__main__':
cic = GCPCluster.get_cloud_init(
projectid='valid-project-id-that-works-for-cluster-creation',
zone='europe-xxxx-x',
machine_type='c2-standard-8', # but occurs with other machine types as well
env_vars={
"EXTRA_PIP_PACKAGES": "joblib==1.3.2 sqlalchemy==2.0.13 scikit-learn==1.3.2 pandas==2.1.4 numpy==1.26.2 nltk==3.6.7"},
)
print(cic)

```

**Anything else we need to know?**:
Error traceback:
```
/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/bin/python3 /home/alexwalterbos/repos/magnet.me/services/recommender/similarity/learn/esco/classifiers/get_cloud_config.py
Traceback (most recent call last):
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/learn/esco/classifiers/get_cloud_config.py", line 6, in
cic = GCPCluster.get_cloud_init(
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/lib64/python3.10/site-packages/dask_cloudprovider/generic/vmcluster.py", line 365, in get_cloud_init
cluster = cls(*args, asynchronous=True, **kwargs)
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/lib64/python3.10/site-packages/dask_cloudprovider/gcp/instances.py", line 634, in __init__
super().__init__(debug=debug, **kwargs)
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/lib64/python3.10/site-packages/dask_cloudprovider/generic/vmcluster.py", line 297, in __init__
super().__init__(**kwargs, security=self.security)
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/lib64/python3.10/site-packages/distributed/deploy/spec.py", line 275, in __init__
super().__init__(
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/lib64/python3.10/site-packages/distributed/deploy/cluster.py", line 70, in __init__
self._loop_runner = LoopRunner(loop=loop, asynchronous=asynchronous)
File "/home/alexwalterbos/repos/magnet.me/services/recommender/similarity/venv/lib64/python3.10/site-packages/distributed/utils.py", line 533, in __init__
raise RuntimeError(
RuntimeError: Constructing LoopRunner(loop=loop) without a running loop is not supported
```

**Environment**:

- Dask version: '2023.12.1'
- Python version: 3.10.13
- Operating System: Fedora Linux `6.6.8-200.fc39.x86_64`
- Install method (conda, pip, source): pip

Thanks in advance for any assistance you can provide.