Do not show primary email as secondary email in Admin view

What does this MR do and why?

Fixes #346274 (closed)

Recently we introduced that the primary email, when verified, is also added to the Emails table (where other "secondary emails" are). We adjusted User facing view, to not list the primary email twice, but forgot about Admin view. This MR is fixing that.

Screenshots or screen recordings

In Admin view, User without secondary email has no listing of secondary email at all, primary email is not repeated here (compare with issue screenshot)

How to set up and validate locally

Take any account and check the user in admin view.

MR acceptance checklist

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