fix(FormField): missing conditions to apply container classes

[Akryum]

🔗 Linked issue

❓ 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

If the label prop is not passed but the label slot is used, or if a description is put but no label, the container class is ignored.

📝 Checklist

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

[pkg-pr-new]

pnpm add https://pkg.pr.new/@nuxt/ui@2631

commit: 2fe77a2

[benjamincanac]

Thanks @Akryum! 😊