fix(SelectMenu): wrong displayed value if items not avaiable

[rdjanuar]

🔗 Linked issue

Resolves #5356

• 📖 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

When we manually filter the items, the resulting array might be empty ([]). In this situation, the displayed value should be the label, instead of the raw value itself. I am using a cache for props.items and props.modelValue to fix the lookup of the displayedValue

📝 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@5620

commit: e718eef