The Firefox ESR release has not received this automation yet. But the web is moving towards encryption for whole sites, not just credential pages.

[I had one of my users flag a site for me at work yesterday because of this - the login page was unsecured, and used an iframe for the https link to the login page. It was flagged correctly, but confused the user, as they have used this site previously. I reached out to the site owner and it will probably be adjusted.]