Add ARIA live attribute to all AJAX updated areas

So that screenreaders will report on updates to the page.

app/templates/partials/jobs/count.html

@@ -5,6 +5,7 @@
     data-module="update-content"
     data-resource="{{url_for(".view_job_updates", service_id=current_service.id, job_id=job_id)}}"
     data-key="counts"
+    aria-live="polite"
   {% endif %}
 >
 

app/templates/partials/jobs/notifications.html

@@ -5,6 +5,7 @@
     data-module="update-content"
     data-resource="{{url_for(".view_job_updates", service_id=current_service.id, job_id=job_id)}}"
     data-key="notifications"
+    aria-live="polite"
   {% endif %}
 >
 

app/templates/partials/jobs/status.html

@@ -3,6 +3,7 @@
     data-module="update-content"
     data-resource="{{url_for(".view_job_updates", service_id=current_service.id, job_id=job_id)}}"
     data-key="status"
+    aria-live="polite"
   {% endif %}
 >
 

app/templates/views/dashboard/today.html

@@ -5,6 +5,7 @@
   data-resource="{{url_for(".service_dashboard_updates", service_id=current_service.id)}}"
   data-key="today"
   data-interval-seconds="2"
+  aria-live="polite"
 >
   <h2 class="heading-medium">
     In the last 7 days