The plugin incorrectly escapes some characters

[anton-vlasenko]

Steps to reproduce the bug:

1. Click on Appearance -> Create Block Theme.
2. Choose Create blank theme.
3. Use ABC'"!@#$%^&*()\|/ for Theme Name, Theme Description, Author.
4. Click Generate.
5. Go to the wp-content folder and inspect the theme's style.css, e.g. src/wp-content/themes/abc/style.css.

This is where the bug occurs:

6. Observe that the ABC'"!@#$%^&*()\|/ string is not escaped correctly in the style.css. There are redundant \ characters -> ABC\'\"!@#$%^&*()\\|/
7. Go to Appearance -> Themes. Theme name is not displayed correctly on the front-end.