Populate User name field during social auth

[Andrew-Chen-Wang]

Description

The "name" field is not filled with social authentication using django allauth due to removing the first and last name field in the User model. This PR fills in the name field.

Checklist:

• I've made sure that tests are updated accordingly (especially if adding or updating a template option)
• I've updated the documentation or confirm that my change doesn't require any updates

Rationale

To fill in the name field during social auth

[browniebroke]

Do you have an exemple of a social provider I could use to test this without too much setup? Also, it would be nice if we could write an automated test for it, this is

[browniebroke]

I seems like it would be more consistent with django-allauth if we were to do it in the save_user() method: https://github.com/pennersr/django-allauth/blob/7060e3fb6e00f01bd881890546244670929b5cf3/allauth/account/adapter.py#L224-L251

Unless there a specific reason not to?

[Andrew-Chen-Wang]

It's been awhile, but I believe save_user isn't actually used for social registration (i.e. it's not called if you use auto signup):

save_user(self, request, sociallogin, form=None): Populates and saves the User instance (and related social login data). The signup form is not available in case of auto signup.

https://django-allauth.readthedocs.io/en/latest/advanced.html?highlight=populate_user#creating-and-populating-user-instances

[Andrew-Chen-Wang]

Thanks for the review

Do you have an exemple of a social provider I could use to test this without too much setup?

I find Google the easiest and Twitter the second easiest to set up.

Also, it would be nice if we could write an automated test for it

We could add mock requests? Otherwise, not sure whether adding these OAuth providers and a bot for automated testing will trigger a captcha warning.