[EmptyState] Support ref as prop and accept ReactNode for text

[ravisuhag]

Summary

EmptyState is a custom component for displaying empty/placeholder states. Several improvements around CSS cleanup and flexibility.

Improvements

3. Accept ReactNode for text content

Text props should accept ReactNode instead of just string to allow rich content.

Moved to Cross-Cutting Issues

The following items have been moved to cross-cutting issues that address them across all components:

• Replace hardcoded CSS values with design tokens (Replace hardcoded CSS values with design tokens #672)
• Forward HTML attributes (Forward HTML attributes (spread rest props) #674)
• Clean up deprecated code (Clean up deprecated code, unused CSS, and legacy patterns #682)

Files

• packages/raystack/raystack/components/empty-state/