fix(ScrollControls): cache ReactDOM root for React 19 compatibility

[iamadagostino]

Description

Prevent duplicate createRoot() calls by caching the root instance on the DOM element, fixing React 19 error on component remount.

Why

React 19 throws an error when ReactDOM.createRoot() is called multiple times on the same container. ScrollHtml was creating a new root on each remount, breaking compatibility with React 19.

What

• Cache ReactDOM root instance on the DOM element using __r3_root property
• Reuse cached root on component remount
• Fixes React 19 compatibility while maintaining backwards compatibility

Checklist

• Ready to be merged

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