Fix misleading ListItemComponent JSDoc in VirtualizedList types

[aravi365]

Summary

I added ListItemComponent to these types in #57754 and got the comment wrong. It says the component receives index and separators "in addition to the data provided to renderItem", which reads as if renderItem doesn't get them. It does. _renderElement in VirtualizedListCellRenderer.js passes the same item, index and separators to both.

This fixes that sentence and mentions the one thing that actually is different, which is precedence. When both are set, ListItemComponent wins and _renderElement logs a warning saying so.

Changelog:

[INTERNAL] [FIXED] - Fix JSDoc for ListItemComponent in VirtualizedList types

Test Plan

Comment-only change in a .d.ts, no type changes. Checked the wording against _renderElement:

if (ListItemComponent) {
  return (
    <ListItemComponent item={item} index={index} separators={this._separators} />
  );
}
if (renderItem) {
  return renderItem({item, index, separators: this._separators});
}