Remove "metamta.insecure-auth-with-reply-to" Config option
I don't recall it ever coming up since then, and a survey of a subset of hosted instances (see T11760) reveals that no instances are using this option today. Presumably, even Quora has completed the onboarding discussed in D842, if they still use Phabricator. This option generally does not seem very useful outside of very unusual/narrow cases like the one Quora had.
This would be relatively easy to restore as a local patch if installs do need it, but I suspect this has no use cases anywhere.
Test Plan: Grepped for option, blame-delved to figure out why we added it in the first place, surveyed instances for usage.
Reviewed By: amckinley
Maniphest Tasks: T7477
Differential Revision: https://secure.phabricator.com/D19949