fix: do not externalize monorepo modules, revert #9140

[antfu]

Description

Revert #9140, since it introduced more serious breakage #9202, I think it's better to revert it for now (as SvelteKit no longer needs it either). An alternative solution is under exploring in #10254 for the future.

Additional context

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.

[patak-dev]

/ecosystem-ci run

[vite-ecosystem-ci]

📝 Ran ecosystem CI: Open

suite	result
astro	✅ success
iles	✅ success
ladle	❌ failure
laravel	❌ failure
marko	✅ success
nuxt-framework	✅ success
rakkas	✅ success
storybook	❌ failure
svelte	✅ success
vite-plugin-ssr	❌ failure
vite-setup-catalogue	✅ success
vitepress	❌ failure
vitest	❌ failure
windicss	✅ success

[patak-dev]

@antfu would it be ok to release this as part of 3.2? We can release a beta today/tomorrow and release stable after ViteConf. Or should we also port it to 3.0 and 3.1? cc @bluwy

[antfu]

I would prefer to backport it to 3.1

[antfu]

fixed by #10254