That toggle isn’t there for us, when using the “Use all from…” taxonomy. https://i.imgur.com/JSdepAl.png
Or do you mean, if using a dropdown that is set to “Use all from…”, it will now cause the dropdown to hide the terms that don’t have any posts? That would be ideal, but that doesn’t seem to be the case…
We have this page, with 2 dropdown filters. The Category filter is showing ALL categories, even if some of them don’t have any posts in them.