Handle missing keys in Google SSO integration

[cal-itp-sentry]

Sentry Issue: BENEFITS-5P

KeyError: 'locale'
  File "django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "django/views/decorators/http.py", line 64, in inner
    return func(request, *args, **kwargs)
  File "django_google_sso/views.py", line 98, in callback
    user = user_helper.get_or_create_user()
  File "django_google_sso/main.py", line 117, in get_or_create_user
    "locale": self.user_info["locale"],

[thekaveman]

Fixed with the latest version of django-google-sso, see #1956