middlewares: stop maintaining in-session reference to service (#61508)

#61199 allows us to use direct request attribute in order to
    maintain such a reference

src/authentic2_cut/apps.py

@@ -28,6 +28,7 @@ from django.utils.timezone import now, utc
 from django.urls import reverse_lazy
 
 from authentic2.constants import AUTHENTICATION_EVENTS_SESSION_KEY
+from authentic2.utils.service import get_service, set_service
 
 logger = logging.getLogger(__name__)
 
@@ -619,7 +620,7 @@ class AppConfig(django.apps.AppConfig):
         from authentic2.middleware import StoreRequestMiddleware
         request = StoreRequestMiddleware.get_request()
         if request:
-            request.session['service_slug'] = service.slug
+            set_service(request, service)
 
     def cut_event_sso_success(self, idp, service, user, **kwargs):
         msg = u'connexion à %s' % service.name
@@ -719,7 +720,9 @@ class AppConfig(django.apps.AppConfig):
         user.attributes.validated = True
         user.attributes.validation_context = 'FC'
         user.attributes.validation_date = now().date()
-        partner = request.session.get('service_slug')
+        partner = get_service(request)
+        if partner:
+            partner = partner.slug
         if hasattr(request, 'partner'):
             partner = (request.partner and request.partner.get('ou_slug')) or partner
         if partner:

src/authentic2_cut/middlewares.py

@@ -40,7 +40,6 @@ class CUTMiddleware(MiddlewareMixin):
         if hasattr(request, 'session'):
             if not domain:
                 domain = request.session.get('cut_domain')
-            request.service_slug = request.session.get('service_slug', None)
 
         if not domain:
             domain = getattr(request, 'domain', None)
@@ -103,6 +102,5 @@ class CUTMiddleware(MiddlewareMixin):
 
     def process_response(self, request, response):
         if hasattr(request, 'session'):
-            request.session['service_slug'] = getattr(request, 'service_slug', None)
             self.process_request(request)
         return response