feat(NavigationMenu): add nested children support for vertical collapsed menu

[edimitchel]

🔗 Linked issue

Resolves #4543

❓ 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

This PR is making children shown when navigation menu is vertical and collapsed.
It only works for one level and with this PR, multi level is supported.

I did some changed which I expect question or negative feedback:

• withLabel slot props which helps me to reuse the template but with text (as in popover, we can show label, where is collapsed mode it doesn't for first level)
• replacing ui styles depending to the withLabel to match colors

Can someone help me to change properly the direction of the arrow ?

📝 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@5517

commit: 7bd4537