Support stripe-away slot of ClientOnly on SSG

[antfu]

Clear and concise description of the problem

It's common to encounter errors when using client-side only package. Even with <ClientOnly>, the users need to handle that carefully as the import can still be synchronized.

Suggested solution

We do a transform to Vue file that removes the content of <ClientOnly>. Similiar to nuxt/framework#8713

Alternative

No response

Additional context

No response

Validations

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• Read the Contributing Guide.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.