fix(nuxt): improve types for data fetching with transform

[clarkdo]

🔗 Linked issue

resolves #14437

❓ Type of change

• 🐞 Bug fix (a non-breaking change that fixes an issue)

📚 Description

Current AsyncDataOptions is not able to infer correct type on default option when transform exists, this pr fixes the issue and also improve type inference on composables useAsyncData/useLazyAsyncData/useFetch/useLazyFetch by inferring transformed data instead of transform function.

👉 Migration

⚠️ This is a potential breaking change if the user is using generics explicitly. ⚠️

No migration is needed if you are only using the first generic of useFetch or useAsyncData. But if you were typing more fields, or trying to clone the Nuxt types, you will need to update your types to use (instead of a type for the transform function, you will provide a type for the return value of the transform function).

This will probably not affect you as the types were buggy in this case (which was what this PR was solving).

📝 Checklist

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

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[danielroe]

This looks really nice, thank you! ❤️

Do you think there is a way we can keep this from being a breaking change, e.g. by using a function signature overload?