MDC Select limitation: Focus state doesn't work for CSS-only selects

[kfranqueiro]

In MDC Select's DOM structure, the element that receives focus is not the element that ripple/states styles are hooked up to. The element that receives focus is above the ripple surface element, which means :focus-within won't work either.

Solving this would require either rethinking the DOM structure, or seeing if we can get away with attaching the ripple to the root element instead (as mentioned in #1725).

This is sort of overshadowed by #1726 anyway, but this issue would still exist even if that were fixed.

[lynnmercier]

Closing as obsolete because CSS only version is removed with #2116