Add a new endpoint for deleting the invitation-id from session.

Used to "log" a user out in the manual invite flow

gregui/api/views/invitation.py

-import logging
 from enum import Enum
+import logging
 from typing import Optional, List
+import structlog
 
 from django.core import exceptions
 from django.db import transaction
@@ -24,7 +25,7 @@ from gregui.api.serializers.invitation import InviteGuestSerializer
 from gregui.mailutils import send_invite_mail
 from gregui.models import GregUserProfile
 
-logger = logging.getLogger(__name__)
+logger = structlog.getLogger(__name__)
 
 
 class InvitationView(CreateAPIView, DestroyAPIView):
@@ -91,9 +92,7 @@ class InvitationView(CreateAPIView, DestroyAPIView):
             # not be verified, but including that check just in case here.
             # If this is the case then there is an unexpected situation, the cancel option
             # should only apply to guests that have not completed the registration
-            logger.warning(
-                f"Attempting to delete invitation for already registered guest with person ID {person_id}"
-            )
+            logger.warning("try_delete_registered_invite", person_id=person_id)
             return Response(status=status.HTTP_400_BAD_REQUEST)
 
         # Delete the person. The delete will cascade and all roles, identities and invitations will be removed.
@@ -109,7 +108,7 @@ class CheckInvitationView(APIView):
     permission_classes = [AllowAny]
     throttle_classes = [AnonRateThrottle]
 
-    def post(self, request, *args, **kwargs):
+    def post(self, request, *args, **kwargs) -> Response:
         """
         Endpoint for verifying and setting invite_id in session.
 
@@ -132,6 +131,16 @@ class CheckInvitationView(APIView):
         request.session["invite_id"] = invite_id
         return Response(status=status.HTTP_200_OK)
 
+    def delete(self, request, *args, **kwargs) -> Response:
+        if "invite_id" in request.session:
+            logging.info(
+                "invitation_session_deleted", invite_id=request.session["invite_id"]
+            )
+            del request.session["invite_id"]
+            return Response(status.HTTP_200_OK)
+
+        return Response(status=status.HTTP_403_FORBIDDEN)
+
 
 class SessionType(Enum):
     INVITE = "invite"
@@ -322,9 +331,7 @@ class ResendInvitationView(UpdateModelMixin, APIView):
         if non_expired_links.count() > 0:
             if non_expired_links.count() > 1:
                 # Do not expect this to happen
-                logger.warning(
-                    f"Person with ID {person_id} has multiple invitation links"
-                )
+                logger.warning("found_multiple_invitation_links", person_id=person_id)
 
             # Just resend all and do not create a new one
             for link in non_expired_links:
@@ -339,9 +346,7 @@ class ResendInvitationView(UpdateModelMixin, APIView):
                 # Do not expected that a person has several open invitations, it could happen
                 # if he has been invited by different sponsor at the same time, but that
                 # could be an indication that there has been a mixup
-                logger.warning(
-                    f"Multiple invitations exist for person with ID {person_id}"
-                )
+                logger.warning("found_multiple_invitations", person_id=person_id)
 
             for invitation in invitations_to_resend:
                 invitation_link = InvitationLink.objects.create(