BUG: CSS added via custom code persists after custom code component is removed  #38

GrapesJS version

• I confirm to use the latest version of GrapesJS

What browser are you using?

any

Reproducible demo link

https://grapesjs.com/demo

Describe the bug

How to reproduce the bug?

1. Add custom code component with HTML + CSS
2. Delete custom code component.

What is the expected behavior?
All code should be removed, including CSS

What is the current behavior?
custom CSS is not being removed, though the rest is.

Code of Conduct

• I agree to follow this project's Code of Conduct