for react 19

[lerte]

the peerDependencies of use-sync-external-store 1.4.0 is "react": "^16.8.0 || ^17.0.0 || ^18.0.0 || ^19.0.0"

Closes

✅ Pull Request Checklist:

• Included link to corresponding React Spectrum GitHub Issue.
• Added/updated unit tests and storybook for this change (for new code or code which already has tests).
• Filled out test instructions.
• Updated documentation (if it already exists for this component).
• Looked at the Accessibility Practices for this feature - Aria Practices

📝 Test Instructions:

🧢 Your Project:

[reidbarber]

Thanks! Can you sign the CLA then close and re-open this to trigger a new passing build

[snowystinger]

The bump is within the range allowed, what was the issue you found?