feat(empty-state): new SHINE styles and Svelte Component

[mukunku]

Summary

This PR:

• Updates the empty state component according to the latest designs.
• Introduces a new EmptyState Svelte component
• Updates ExpandingInput to Svelte 5 syntax.
  • Turns out expanding input was slightly broken after my TextArea update. So thought I'd fix that in this PR.

How to Test

• Review the updated Stacks Docs page: https://deploy-preview-2100--stacks.netlify.app/product/components/empty-states/
• Check out the new EmptyState Svelte component: https://deploy-preview-2100--stacks-svelte.netlify.app/?path=/docs/components-emptystate--docs
• Confirm ExpandingInput works again: https://deploy-preview-2100--stacks-svelte.netlify.app/?path=/docs/components-expandinginput--docs

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🦋 Changeset detected

Latest commit: 306a2f3e8bbcc93381b7e56a60980e0cc06f16b1

The changes in this PR will be included in the next version bump.

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