Svelte: Fix Vite 8 + Vitest breaking rolldown deps scanner

[JReinhold]

Closes #34304

What I did

Checklist for Contributors

Testing

The changes in this PR are covered in the following automated tests:

• stories
• unit tests
• integration tests
• end-to-end tests

Manual testing

See reproduction in issue.

Documentation

• Add or update documentation reflecting your changes
• If you are deprecating/removing a feature, make sure to update
  MIGRATION.MD

Checklist for Maintainers

• When this PR is ready for testing, make sure to add ci:normal, ci:merged or ci:daily GH label to it to run a specific set of sandboxes. The particular set of sandboxes can be found in code/lib/cli-storybook/src/sandbox-templates.ts

• Make sure this PR contains one of the labels below:

  Available labels

  • bug: Internal changes that fixes incorrect behavior.
  • maintenance: User-facing maintenance tasks.
  • dependencies: Upgrading (sometimes downgrading) dependencies.
  • build: Internal-facing build tooling & test updates. Will not show up in release changelog.
  • cleanup: Minor cleanup style change. Will not show up in release changelog.
  • documentation: Documentation only changes. Will not show up in release changelog.
  • feature request: Introducing a new feature.
  • BREAKING CHANGE: Changes that break compatibility in some way with current major version.
  • other: Changes that don't fit in the above categories.

🦋 Canary release

This PR does not have a canary release associated. You can request a canary release of this pull request by mentioning the @storybookjs/core team here.

core team members can create a canary release here or locally with gh workflow run --repo storybookjs/storybook publish.yml --field pr=<PR_NUMBER>

Summary by CodeRabbit

• Chores
  • Updated internal import structure for improved package organization in the Svelte preview renderer.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 97716bd and fd0b833.

📒 Files selected for processing (1)

• code/renderers/svelte/static/PreviewRender.svelte

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📝 Walkthrough

Walkthrough

This PR updates the import statement in PreviewRender.svelte to source DecoratorHandler from the Storybook internal package path rather than a relative file reference, accompanied by a comment documenting this constraint.

Changes

DecoratorHandler Import Path Consolidation

Layer / File(s)	Summary
DecoratorHandler import and documentation code/renderers/svelte/static/PreviewRender.svelte	Import path changed from relative ./DecoratorHandler.svelte to internal package path @storybook/svelte/internal/DecoratorHandler.svelte with explanatory comment block.

🎯 1 (Trivial) | ⏱️ ~3 minutes

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