Add consistent validation of email address in client and server

[mdaoustUdeS]

Context

During the Sign up, when the email field is validated, the message Please enter an email address. appear when there is no character before or after the @ (at) symbol.

Problem

This message don't appear when there is no . (dot) after the @ (at) symbol (aka, when a TLD is enter as the email domain).

When we press Sign up, we receive an 400 Bad Request from the server.

Validation of email address should be consistent.

Information

It is technically possible for the owner of a TLD to add MX records in the TLD zone.

Reference

https://serverfault.com/a/721929