Disable sending activation email also when doing external_auth and setti...

...ng BYPASS_ACTIVATION_EMAIL_FOR_EXTAUTH=True


Sorry for this....it was a previous PR with some discussions, but wrong branch and I was forced to clean my master branch
Also, I would swap the order to be more aligned with your comment "external auth with bypass activated":
```python
send_email = (
    not settings.FEATURES.get('AUTOMATIC_AUTH_FOR_TESTING') and
    not (DoExternalAuth and settings.FEATURES.get('BYPASS_ACTIVATION_EMAIL_FOR_EXTAUTH'))
)
```