BUG: Incompatibility with grape js headless mode

### GrapesJS version

- [x] I confirm to use the latest version of GrapesJS

### GrapesJS MJML version

- [x] I confirm to use the latest version of GrapesJS MJML

### What browser are you using?

Not applicable (it's running on a server)

### Reproducible demo link

https://codesandbox.io/p/sandbox/m86rgn

### Describe the bug

**How to reproduce the bug?**
1. Init GrapeJS in headless mode
2. Try to run command mjml-code-to-html

**What is the expected behavior?**
The html is created (and does not rely on window since we run it in headless mode).

**What is the current behavior?**
We have this error :
```
window is not defined
ReferenceError: window is not defined
at Object.moduleId [as 480] ...

```
If is necessary to execute some code in order to reproduce the bug, paste it here below:
```js
const editor = grapesjs.init({
telemetry: false,
headless: true,
plugins: [usePlugin(grapesJSMJML, { useCustomTheme: false })],
projectData: {"test": "test"} as ObjectAny,
});
console.log(emailEditor.runCommand('mjml-code-to-html').html.toString());
```

### Workaround:
We found a solution by importing global-jsdom/register, that gives a mock of window.

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct