fix: importing unscoped style between multiple sfc's

[Kolobok12309]

Description

Sometimes when you import same css (not scoped) file between multiple sfc's you get error while build #5977, #8660

[vite:vue] Cannot read properties of undefined (reading 'scoped')

It not very stable error, in out project we only get it in docker, but all be fine on local machine

Reproduce repo from my local machine

Additional context

Multiple descriptors try attach to same filename and style tag can has another index. I fix index to first descriptor and don't reassign it. But finding of index is not so good code

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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• Read the Contributing Guidelines.
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[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/@vitejs/plugin-vue@612

npm i https://pkg.pr.new/@vitejs/plugin-vue-jsx@612

commit: 26afe8f