Use "private" namespace for icons URL

aleksis/core/urls.py

@@ -320,7 +320,7 @@ urlpatterns = [
         name="assign_permission",
     ),
     path("pdfs/<int:pk>/", views.RedirectToPDFFile.as_view(), name="redirect_to_pdf_file"),
-    path("icons/", include("dj_iconify.urls")),
+    path("__icons__/", include("dj_iconify.urls")),
 ]
 
 # Use custom server error handler to get a request object in the template