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

### GrapesJS version

- [X] 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.

[gjs.webm](https://github.com/user-attachments/assets/3fbd9a6d-ad0e-4fc6-add8-7cf31ae9293c)

### Code of Conduct

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

Start with the reproducible demo at https://grapesjs.com/demo and follow the custom code component removal path after adding HTML and CSS. Done means deleting the component also removes its custom CSS, while the existing HTML and other code removal behavior remains intact.

Written by the indexing model from the issue text.