Show sent, not pending numbers on the dashboard

The dashboard should only talk about notifications that are *successful* or
*failed*. It should not count notifications that are still queued.

This will stop:
- a situation like ‘0 emails, 14.1% failed’
- the big numbers and the template statistics numbers not adding up to
  the same total

app/templates/views/dashboard/today.html

@@ -13,9 +13,9 @@
   <div class="grid-row bottom-gutter">
     <div class="column-half">
       {{ big_number_with_status(
-        statistics.get('emails_delivered', 0),
-        'email' if statistics.get('emails_delivered') == 1 else 'emails',
-        statistics.get('emails_failed'),
+        statistics.emails_sent,
+        'email' if statistics.emails_sent == 1 else 'emails',
+        statistics.emails_failed,
         statistics.get('emails_failure_rate', 0.0),
         statistics.get('emails_failure_rate', 0)|float > 3,
         failure_link=url_for(".view_notifications", service_id=current_service.id, template_type='email', status='failed')
@@ -23,9 +23,9 @@
     </div>
     <div class="column-half">
       {{ big_number_with_status(
-        statistics.get('sms_requested', 0),
-        'text message' if statistics.get('sms_requested') == 1 else 'text messages',
-        statistics.get('sms_failed'),
+        statistics.sms_sent,
+        'text message' if statistics.sms_sent == 1 else 'text messages',
+        statistics.sms_failed,
         statistics.get('sms_failure_rate', 0.0),
         statistics.get('sms_failure_rate', 0)|float > 3,
         failure_link=url_for(".view_notifications", service_id=current_service.id, template_type='sms', status='failed')