FIX: Use addresses to compare email header (PR #14509)

Usually, when an email is received a user lookup is performed using the email address found in the From header. When an email has an X-Original-From header, if it is equal to Reply-To then it uses that one instead. The comparison was sensitive to whitespaces and other insignificant characters such as quotes because it reconstructed the From header.

For the fixture added in this commit, it compared the reconstructed From header John Doe <> with the Reply-To header "John Doe" <>.