fix(qwik-nx): remove duplicate css variable

[maartentibau]

What is it?

• [ ] Feature / enhancement
• [ ] Bug
• [x] Docs / tests

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. List any dependencies that are required for this change.

Use cases and why

• 1. One use case
• 2. Another use case

Screenshots/Demo

Checklist:

• [x] My code follows the developer guidelines of this project
• [x] I have performed a self-review of my own code
• [ ] I have made corresponding changes to the documentation
• [ ] Added new tests to cover the fix / functionality

[dmitry-stepanenko]

Hey @maartentibau, thank you for the contribution!