fix: add compatibility with hable

[wattanx]

🔗 Linked issue

#1000

❓ 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 like performance)
• ✨ New feature (a non-breaking change that adds functionality)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

In the case of hable, since the hook does not return a function, an error is output when executing nuxt.callHook('restart').

unsub is not a function

In nuxt 2.17.3, it is migrated to hookable, so maybe this support is not needed.

📝 Checklist

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