Upgrade to Storybook 8 in FAST Foundation

[radium-v]

Pull Request

📖 Description

This PR updates the FAST Foundation project to use Storybook 8.

• Switch the Storybook configuration from Webpack to Vite (@storybook/html-vite)
• Update the ESLint config in Foundation to force type-only imports to use import type ... from ...
• Removes "sideEffects": false from the package.json side effect config is no longer affected

🎫 Issues

#6698

👩‍💻 Reviewer Notes

Most of the changes in this PR can be categorized into a few manageable piles:

• All type-only imports and exports have to be explicitly separated out into their own statements.
• Storybook changed its root element from #root to #storybook-root, and sometimes Playwright thinks it's okay to continue even though the page hasn't finished defining the components.

📑 Test Plan

All tests in fast-foundation should pass as expected, though some individual test modules might be flaky in different environments.

✅ Checklist

General

• I have included a change request file using $ yarn change
• I have added tests for my changes.
• I have tested my changes.
• I have updated the project documentation to reflect my changes.
• I have read the CONTRIBUTING documentation and followed the standards for this project.

⏭ Next Steps

#6855

[radium-v]

I checked to see if anything we generate is affected by the removal of sideEffects: false - the only file that changed in dist/ was custom-elements.json, and all that changed was the sort order.

I'm still investigating if consumers of @microsoft/fast-foundation rely on us to have sideEffects: false for tree-shaking to work for them.

[bheston]

Wow, thanks for doing this! I'm surprised there weren't more changes needed in the Stories or helper functions.