feat: prefill custom fields in the registration form with TPA data

(cherry picked from commit f99b720)

lms/envs/common.py

@@ -4534,6 +4534,12 @@ def _make_locale_paths(settings):  # pylint: disable=missing-function-docstring
 
 REGISTRATION_EXTENSION_FORM = None
 
+# .. setting_name: REGISTRATION_EXTENSION_FORM_FIELDS_TPA_OVERRIDES
+# .. setting_default: []
+# .. setting_description: List of custom fields included in the registriation
+#      form extension to be prefilled with third party auth data.
+REGISTRATION_EXTENSION_FORM_FIELDS_TPA_OVERRIDES = []
+
 # Identifier included in the User Agent from open edX mobile apps.
 MOBILE_APP_USER_AGENT_REGEXES = [
     r'edX/org.edx.mobile',

openedx/core/djangoapps/user_authn/views/registration_form.py

@@ -1134,8 +1134,13 @@ def _apply_third_party_auth_overrides(self, request, form_desc):
                             current_provider.skip_registration_form and enterprise_customer_for_request(request)
                         ) or current_provider.sync_learner_profile_data
                     )
+                    registration_fields = (
+                        self.DEFAULT_FIELDS
+                        + self.EXTRA_FIELDS
+                        + settings.REGISTRATION_EXTENSION_FORM_FIELDS_TPA_OVERRIDES
+                    )
 
-                    for field_name in self.DEFAULT_FIELDS + self.EXTRA_FIELDS:
+                    for field_name in registration_fields:
                         if field_name in field_overrides:
                             form_desc.override_field_properties(
                                 field_name, default=field_overrides[field_name]