fix: make setup script compilation respect __VUE_PROD_DEVTOOLS__

[blakjak44]

Description

Ensure that the setup section is available in Vuejs Devtools when building with __VUE_PROD_DEVTOOLS__: true.

Additional context

Original fix. Possible regression since then? vitejs/vite#4984
Another report with example reproduction: vuejs/devtools#1940

Not sure if defineExpose is supposed to play a role here.

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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[adamdehaven]

Is there any plan to merge this fix?

[CreeTar]

can we get a comment for this issues anniversary? hope 2 months is enough ;)