Revert "Make only message sending run on_commit"

This reverts commit 3bae1a9a.

aleksis/core/celery.py

 import os
-from functools import partial
 
 from django.db import transaction
 
@@ -12,8 +11,12 @@ app.config_from_object("django.conf:settings", namespace="CELERY")
 app.autodiscover_tasks()
 
 
-def _amqp_send_task_message_on_commit(*args, **kwargs):
-    transaction.on_commit(partial(app.amqp.send_task_message, *args, **kwargs))
+class OnCommitTask(app.Task):
+    """Task that is delayed at least until the current transaction commits."""
+    def delay(self, *args, **kwargs):
+        def _real_delay():
+            return super().delay(*args, **kwargs)
+        transaction.on_commit(_real_delay)
 
 
-app.amqp.send_task_message = _amqp_send_task_message_on_commit
+app.Task = OnCommitTask