fix: support custom css name by no cssCodesplit

[poyoho]

Description

fix: #4863
fix: #9732

Additional context

support custom css name by no cssCodesplit.

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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.
• 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]

I would consider this more as a fix for an unintentional regression that a feat. So I think we could merge this one and release it in a patch. @poyoho do you know how this broke in Vite 3?

I don't know if we should close #4863 though. At least we should discuss in a team meeting if this is going to be the way this feature is implemented and document it. Another option would be to expose a new config css.bundleName or something similar.

[poyoho]

may be I confuse what issues ask for. The issues ask for cssCodeSplit: false would output index.css. It mean style.css need to configureable. I think #4597 #4863 #9732 are ask for the same feature too.

And I checkout to 2.5.0, It seems not fix this problem.

[patak-dev]

I'm a bit lost here. IIUC, this PR only adds a test case now and shows that #9732 wasn't an issue since the file name for style.css is correctly modified https://github.com/vitejs/vite/pull/9747/files#diff-903a4c1ecc75694a61c610989146d12e745eec8b85b6dded38930d5a71377bd8R26 ?

[poyoho]

updated😁.

[bluwy]

In the meeting when we discussed this, we decided to re-use the library mode name as the CSS file name instead so we can avoid an option, but that would be for Vite 6.