fix(RadioGroup): rendering empty slots

[hacknug]

🔗 Linked issue

No issue opened. Easy fix.

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

RadioGroup component was missing a conditional to render its nested Radio slots. I also added a test to ensure there are no regressions related to this in the future.

This issue might affect v3 too. I can check and port the changes over there if necessary.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.