Reimplement radio group to use primary color token

[PelayoFelgueroso]

Checklist
(Check off all the items before submitting)

• Build process is done without errors. All tests pass in the /lib directory.
• Self-reviewed the code before submitting.
• Meets accessibility standards.
• Added/updated documentation to /website as needed.
• Added/updated tests as needed.

Purpose
The component was using “secondary color” token instead of the primary one, being inconsistent with the rest of the components.