Interrapt G26

Description:New mentor should be able to be created only with valid e-mails where the prefix is on the left of the simbol and the domain appears on the right of the simbol.

Steps to reproduce:
1.Navigate to the website interrapt
2.Login
3.Click on mentors page in the side bar menu
4.Click 'CREATE' button
5.Fill 'Name' field with valid data
6.Fill 'Surname' field with valid data
7.Fill 'e-mail' field with 'john@'
8.Fill other blank field with valid data
9.Click on 'Create'

Expected result: There should be a message that 'e-mail' field accepts only valid e-mails.

Actual result: 'New mentor is created successfully' message pops up and new mentor is created.