ToolkitProvider default applyClassesTo should always be 'scope'

[heswell]

If user doesn't explicitly configure the applyClassersTo prop, then the top level ToolkitProvider will default to root, nested Providers will default to scope. I think the default should always be scope, here's why:

In root mode, classnames are applied to the document element in a useLayoutEffect hook. If any other components in the app also rely on a useLayoutEffect hook, these will execute first, it's bottom-up order. If any of these are using the useLayoutEffect to measure rendered items (a very common use case), they will be doing so, first time around, before the theme classnames have been applied to the document element so no theme variables will be in scope and measurements are highly likely to be wrong.

If there is a single child under the root Provider, I'd suggest that the default would be to apply the theme classnames there.

[mark-tate]

We are happy with the default being root as per most other component libraries, measuring elements via useLayoutEffect should be continuous. We are closing out existing discussions, so feel free to create as an issue if you want to continue the discussion.