Allow to search for user by secondary email address

Description

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. Please see [1].

Proposal

Allow to search not only by the primary, but also by any additonal email address of a user, in the Users search bar in the admin interface.

Links / references

[1] #23647 (moved)