According to reports of folks who have lost their authenticator-hosting phone (please see https://community.secondlife.com/forums/topic/521592-question-lost-my-phone-and-now-unable-to-access-my-account-due-to-mfa/), it's no longer possible to access the "Disable Multifactor Identification via Email" selection because the whole dashboard is now behind MFA for their accounts.
In fact, they can't access Canny feedback either, which is why I'm submitting this for them. (I did try to use an unauthenticated Chrome browser and ran into the same problem, so it appears to repro.)
I understand the dashboard was only recently MFA-protected, so this seems plausible, but some alternate flow is going to be needed. (It doesn't seem practical to send these all through Support—and if that's the direction going forward, the dashboard option needs deletion for "If you have lost your authenticator and would like to remove your MFA…" which is no longer possible.)