'username' lookup (if set using DJANGO_REST_LOOKUP_FIELD = 'username') cannot validate the email validation

[abdullah131566]

If I set the lookup field to be username instead of email, the POST request gives error "Enter a valid email address."

Steps to reproduce:

1. Add this to settings.py

DJANGO_REST_LOOKUP_FIELD = 'username'

2. Send a POST request with following body content:

{ "email": "someusername123" }

Expected behavior
The keyname must be dynamic and not always be the 'email' in the POST request body. The respective field validations should run based on the declared field as described above.