remove unneccessary duped lines

as per pr comments

app/commands.py

@@ -278,8 +278,6 @@ def populate_annual_billing(year):
                                                      free_sms_fragment_limit=free_allowance[0],
                                                      financial_year_start=int(year))
 
-    db.session.commit()
-
 
 @notify_command(name='list-routes')
 def list_routes():

app/dao/fact_billing_dao.py

@@ -161,7 +161,6 @@ def fetch_letter_line_items_for_all_services(start_date, end_date):
     ).join(
         FactBilling, FactBilling.service_id == Service.id,
     ).filter(
-        FactBilling.service_id == Service.id,
         FactBilling.bst_date >= start_date,
         FactBilling.bst_date <= end_date,
         FactBilling.notification_type == LETTER_TYPE,