CVE-2022-0869: Open Redirect in django-spirit

The vulnerability stems from direct use of Django's redirect() with user-controlled 'next' parameters without proper validation. The patch introduced a safe_redirect helper that implements url_has_allowed_host_and_scheme checks. The identified functions were all modified in the commit to replace raw redirect() calls with safe_redirect, indicating they previously lacked validation. These functions handle authentication-related flows (login/logout/registration) where the 'next' parameter is commonly used, making them prime targets for open redirect exploitation when unvalidated.