Hello ! As of /e/OS 1.9, that functionality doesn’t seem to have been brought back, it’s still “To disable this SIM, remove the SIM card” 
That’s a huge step back from previous versions of /e/OS, and seemingly contradicts /e/'s very own article about Dual SIMs → Manage Dual SIMs
I hope that the developpement team will take an updated look at this feature, that people have been asking for 