scim: Use setattr to set request.user as scim_client.

This is a type-unsafe workaround before we can fix the problem that
django_scim2 relies on request.user being present to authenticate
requests.

Signed-off-by: Zixuan James Li <p359101898@gmail.com>

zerver/middleware.py

@@ -786,5 +786,7 @@ def process_request(self, request: HttpRequest) -> Optional[HttpResponse]:
         # so we can assign the corresponding SCIMClient object to request.user - which
         # will allow this request to pass request.user.is_authenticated checks from now on,
         # to be served by the relevant views implemented in django-scim2.
-        request.user = scim_client
+        # Since request.user must be a UserProfile or AnonymousUser, setattr is a type-unsafe
+        # workaround to make this monkey-patching work.
+        setattr(request, "user", scim_client)
         return None