fix(tagsinputformdemo): fix issue where the demo form is not reactive

[AloisH]

🔗 Linked issue

#1071

❓ Type of change

• 📖 Documentation (updates to the documentation, readme or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ 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

I had to change the v-slot to use the componentField instead of value

Resolve #1071

📝 Checklist

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