fix(runtim-utils): do not use defu for merging

[wattanx]

🔗 Linked issue

ref: #1078

❓ 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

There were cases where setProps could not overwrite when defu was used.
Therefore, the merging of props will no longer use defu.

[danielroe]

❤️

[sebbayer]

Thanks for the fix!