use ft_notification_status and notifications for job statistics

we previously always read from NotificationHistory to get the
notification status stats for a job. Now, if the job is more than three
days old read from ft_notification_status table, otherwise read from
the notifications table (to keep live updates).

app/dao/fact_notification_status_dao.py

@@ -186,3 +186,14 @@ def fetch_notification_status_totals_for_all_services(start_date, end_date):
     else:
         query = stats
     return query.all()
+
+
+def fetch_notification_statuses_for_job(job_id):
+    return db.session.query(
+        FactNotificationStatus.notification_status.label('status'),
+        func.sum(FactNotificationStatus.notification_count).label('count'),
+    ).filter(
+        FactNotificationStatus.job_id == job_id,
+    ).group_by(
+        FactNotificationStatus.notification_status
+    ).all()

app/dao/jobs_dao.py

@@ -16,7 +16,7 @@ from app.models import (
     JOB_STATUS_PENDING,
     JOB_STATUS_SCHEDULED,
     LETTER_TYPE,
-    NotificationHistory,
+    Notification,
     Template,
     ServiceDataRetention
 )
@@ -25,19 +25,14 @@ from app.variables import LETTER_TEST_API_FILENAME
 
 @statsd(namespace="dao")
 def dao_get_notification_outcomes_for_job(service_id, job_id):
-    query = db.session.query(
-        func.count(NotificationHistory.status).label('count'),
-        NotificationHistory.status
-    )
-
-    return query.filter(
-        NotificationHistory.service_id == service_id
+    return db.session.query(
+        func.count(Notification.status).label('count'),
+        Notification.status
     ).filter(
-        NotificationHistory.job_id == job_id
+        Notification.service_id == service_id,
+        Notification.job_id == job_id
     ).group_by(
-        NotificationHistory.status
-    ).order_by(
-        asc(NotificationHistory.status)
+        Notification.status
     ).all()