Task - RBAC AuthZ - Update compatibility layer to support org roles

Update code on [_authz_get_orgs_for_user](https://github.com/WGU-Open-edX/openedx-platform/blob/9477f62f34da7cf7df6d0f75da5b52a7b90a186b/common/djangoapps/student/roles.py#L504) function once org support is implemented on openex-authz as part of https://github.com/openedx/openedx-authz/issues/172