misc: dont mutate dictionnary during iteration (#44869)

src/authentic2_cut/apps.py

@@ -437,7 +437,7 @@ class AppConfig(django.apps.AppConfig):
             form.initial['preferred_givenname'] = view.token.get('first_name', '')
             form.fields['preferred_givenname'].widget = HiddenInput()
 
-            for name in form.fields:
+            for name in list(form.fields):
                 if 'password' not in name and name not in ('preferred_username', 'preferred_givenname'):
                     form.fields.pop(name)