BUG: Can't export to ZIP/ copy html

### GrapesJS version

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

### What browser are you using?

Firefox, Chrome

### Reproducible demo link

https://app.grapesjs.com/studio

### Describe the bug

**How to reproduce the bug?**
1. Build a website in GrapesJS Studio (Alpha) (mine is 14 pages long, maybe thats the problem)/ load my project
2. Try to export it to ZIP

**What is the expected behavior?**
It is possible to export to Zip or copy the html code

**What is the current behavior?**
It just shows a black screen

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

I can't copy my code because of this bug. But you propably would have to use a website similar to mine. Thats why I used pictures to show the problem


### Code of Conduct

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