Allow to search for user by secondary email address in the admin interface

It is not possible to search for a user by his secondary email address in
the Users search bar in the admin interface(/admin/users). A use-case could
 be that an admin wants to remove a specific secondary email address of an
user, because it interferes with another user. Issue #23761

This commit adds ability to search not only by main email, but also
by any secondary email in the admin interface.