refactor: compatibility the with only MIDDLEWARE

This add the compatiblity for only he new django way of MIDDLEWARE.

eox_nelp/middleware.py

@@ -7,7 +7,6 @@
 """
 from django.conf import settings
 from django.http import parse_cookie
-from django.utils.deprecation import MiddlewareMixin
 from django.utils.translation import gettext_lazy as _
 
 from eox_nelp.edxapp_wrapper.site_configuration import configuration_helpers
@@ -138,19 +137,24 @@ def handler(form_instance, form_desc, required=True):
         return handler
 
 
-class PreserveUserLanguageCookieMiddleware(MiddlewareMixin):
+class PreserveUserLanguageCookieMiddleware:
     """This middleware ensure that in the COOKIES property the LANGUAGE_COOKIE_NAME
     key has to be the cookie sent by the user and not other,
     because it could be modified previously by other.
     eg.
     https://github.com/openedx/edx-platform/blob/open-release/palm.master/openedx/
     core/djangoapps/lang_pref/middleware.py#L61-L62
     """
-    def process_request(self, request):
+    def __init__(self, get_response):
+        self.get_response = get_response
+
+    def __call__(self, request):
         """Process the request to change the language cookie based in original cookie value."""
         original_user_language_cookie = parse_cookie(request.META.get("HTTP_COOKIE", "")).get(
             settings.LANGUAGE_COOKIE_NAME
         )
 
         if original_user_language_cookie:
             request.COOKIES[settings.LANGUAGE_COOKIE_NAME] = original_user_language_cookie
+
+        return self.get_response(request)