fix: do not overwrite rollupOptions.input in dev

[ydcjeff]

Description

fix #6020

rollupOptions.input should not be defined in dev mode unless explicitly added by users since Vite crawls *.html by default.

Additional context

Added dev.spec.ts to test dev command behavior since I can't find the respective file for the tests.

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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]

So with this PR, the issue that @IanVS had in storybook vite builder wouldn't have happened? #5601 (comment). @IanVS maybe you could help to review this PR?

[IanVS]

So with this PR, the issue that @IanVS had in storybook vite builder wouldn't have happened? #5601 (comment). @IanVS maybe you could help to review this PR?

No, my issue was happening in production builds, so I don't think this would have had an impact.

[sibbng]

@ydcjeff Tests are in https://github.com/vitejs/vite/blob/main/packages/vite/src/node/__tests__/build.spec.ts

[ydcjeff]

@ydcjeff Tests are in https://github.com/vitejs/vite/blob/main/packages/vite/src/node/__tests__/build.spec.ts

Is that file for testing build mode? For this PR, it is for testing dev mode.

[sibbng]

@ydcjeff Tests are in https://github.com/vitejs/vite/blob/main/packages/vite/src/node/__tests__/build.spec.ts

Is that file for testing build mode? For this PR, it is for testing dev mode.

It is for testing anything related to build functionality. Tests are not separated per command/mode, It's okay to put them there.