Missing validation on adding special characters only for Emails or User Name

Describe the bug
No 'Validation' message appears when we add only "Arithmetic characters" or Special characters in "User name/Email" field and click on 'check'.
(eg. *-+=^ or #$%@ )

To Reproduce
Steps to reproduce the behavior:
1.Open App on Device
2. Click on "Account" icon
3. Enter User name/Email in "Username or Email" text field.
Note: Password should be only "Arithmetic characters" or Special characters.
(eg. *-+=^ or #$%@ )
4. Click on "Check" button.(at top right corner)

Expected behavior
Validation message should be appear when we click on the "Check" button. it should not allow '' "Arithmetic char" or Special char in "User name/Email" field.

**Screenshots **

• Device: iphone 6 (11.2) , Android s6 (7.0)

Comienza en la pantalla Account y en el campo "Username or Email"; después, sigue el flujo del botón "Check" tanto en iPhone como en Android. Reproduce los casos de entrada mostrados en el issue, como solo *-+=^ o #$%@, y confirma que aparece un mensaje de validación y que los valores se rechazan.