bugfix: send email notification once instead of every minute of the hour

gso/schedules/send_email_notifications.py

@@ -7,7 +7,7 @@ from gso.worker import celery
 
 
 @celery.task
-@scheduler(CronScheduleConfig(name="Send email notifications", hour="4"))
+@scheduler(CronScheduleConfig(name="Send email notifications", hour="4", minute="0"))
 def send_email_notifications() -> None:
     """Run this task every night at 2:30 AM."""
     start_process("task_send_email_notifications")