fix(Calendar): grey out days outside of displayed month

[ac-shadow]

🔗 Linked issue

Resolves #3625

❓ 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

Grayed out the days that are outside of the displayed month.

Comparison between the current and new version:

📝 Checklist

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

[pkg-pr-new]

npm i https://pkg.pr.new/@nuxt/ui@3639

commit: e872b8a

[benjamincanac]

Thanks! 😊