adhocracy4/emails: refactors send_async for use with celery workers (…

…makes it serializable by returning nothing)

adhocracy4/emails/tasks.py

@@ -8,9 +8,9 @@
 def send_async(
     email_module_name, email_class_name, app_label, model_name, object_pk, args, kwargs
 ):
-    imported_module = importlib.import_module(email_module_name)
-    cls = getattr(imported_module, email_class_name)
+    email_module = importlib.import_module(email_module_name)
+    email_class = getattr(email_module, email_class_name)
     model = apps.get_model(app_label, model_name)
     obj = model.objects.get(pk=object_pk)
 
-    return cls().dispatch(obj, *args, **kwargs)
+    email_class().dispatch(obj, *args, **kwargs)