Broken cloud init if ENV contains double quote

**Describe the issue**:

Scheduler will be shutdown by guest OS if any ENVs contain `"`

**Minimal Complete Verifiable Example**:

```python
GCPCluster(
env_vars={"ANY_VAR": '"'}
)
```

The cloud init will contains:
```
...
# Run container:
- 'docker run ... -e GCP_ANY_VAR=""" ...'
...
```
while it should escape `"` propely:
```
...
# Run container:
- 'docker run ... -e GCP_ANY_VAR="\"" ...'
...
```

To fix the problem we have to:
1. Properly refactor the command rendering in cloud-init:
https://github.com/dask/dask-cloudprovider/blob/736842d87779d398273da4aa85681cf072842eb0/dask_cloudprovider/generic/cloud-init.yaml.j2#L59
2. There should be proper error logging to show that cloud init does not pass

**Environment**:

- Dask version: 2024.12.1
- Python version: 3.11
- Operating System: WSL
- Install method (conda, pip, source): poetry