BUG: wrong rendering for the builder

### 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?

Chrome

### Reproducible demo link

https://grapesjs.com/demo-mjml.html

### Describe the bug

**How to reproduce the bug?**
1. ... Import MJML:
```

Hello World!

```
2. ...

Same thing using ``

**What is the expected behavior?**
Hello world should be blue as per the mjml.io demo website
...

**What is the current behavior?**
currently the text is not blue but black
...

If is necessary to execute some code in order to reproduce the bug, paste it here below:
```js
// your code here
```

### Code of Conduct

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