Add scheduled task to send scheduled notifcations.

Fix the query to fetch scheduled notifications.

app/celery/scheduled_tasks.py

@@ -14,13 +14,14 @@ from app.dao.jobs_dao import dao_set_scheduled_jobs_to_pending, dao_get_jobs_old
 from app.dao.notifications_dao import (
     delete_notifications_created_more_than_a_week_ago,
     dao_timeout_notifications,
-    is_delivery_slow_for_provider
-)
+    is_delivery_slow_for_provider,
+    dao_get_scheduled_notifications)
 from app.dao.provider_details_dao import (
     get_current_provider,
     dao_toggle_sms_provider
 )
 from app.dao.users_dao import delete_codes_older_created_more_than_a_day_ago
+from app.notifications.process_notifications import send_notification_to_queue
 from app.statsd_decorators import statsd
 from app.celery.tasks import process_job
 
@@ -46,6 +47,18 @@ def run_scheduled_jobs():
         raise
 
 
+@notify_celery.task(name='send-scheduled-notifications')
+@statsd(namespace="tasks")
+def send_scheduled_notifications():
+    try:
+        for notification in dao_get_scheduled_notifications():
+            send_notification_to_queue(notification, notification.service.research_mode)
+
+    except SQLAlchemyError as e:
+        current_app.logger.exception("Failed to send scheduled notifications")
+        raise
+
+
 @notify_celery.task(name="delete-verify-codes")
 @statsd(namespace="tasks")
 def delete_verify_codes():