Allows set email to a username, does not allow login without proper email formatting

[xstefen]

Describe the bug
Allows set email to a username, does not allow login without proper email formatting

To Reproduce
Steps to reproduce the behavior:

1. In settings->users, change admin user email to a username, for example, 'tehadmin', and Save
2. At this point you will get 500 errors until relogin, so return to login page
3. enter 'tehadmin' for email, see complains requiring an @ and text following
4. Re-roll the container because now you cant login

Expected behavior
username allowed for login, or disallowed to set as email

Environment (please complete the following information):

• docker-compose

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Additional context