fixed issue #25

[bhargavg-amdocs]

Fixed:

1. Native div props support: The {...props} spread on the outer

   passes through all native div props (e.g., onClick, onMouseEnter, data-, aria-, id, title), so the component behaves like a standard div.

2. ClassName merging: Using className={classNames('scrollbar', className)} merges the base 'scrollbar' class with any user-provided className, so both are applied.

3. Prop extraction: Extracting onScroll, onUpdate, scrollOnDOMChange, and cssVarsOnTracks from props prevents them from being spread to the outer div via {...props}, keeping Scrollable-specific props separate from native div props.