Rename dashboard to ‘current alerts’

The dashboard for normal services is quite general, because it tells
you a bit about channels, templates and spend.

What is now the dashboard for broadcast services is much more specific,
therefore less like a dashboard. We can reflect this by giving it a more
specific name. This should reduce the amount of navigation surfing
people need to do in order to find the thing they’re looking for.

app/templates/views/broadcast/tour/5.html

@@ -33,7 +33,7 @@
         </p>
         <p class="govuk-body heading-medium">
           <a class="govuk-link govuk-link--no-visited-state" href='{{ url_for(".service_dashboard", service_id=current_service.id) }}'>
-            Continue to dashboard
+            Continue
           </a>
         </p>
       </div>

app/templates/views/broadcast/tour/6.html

@@ -28,7 +28,7 @@
         </p>
         <p class="govuk-body heading-medium">
           <a class="govuk-link govuk-link--no-visited-state" href='{{ url_for(".service_dashboard", service_id=current_service.id) }}'>
-            Continue to dashboard
+            Continue
           </a>
         </p>
       </div>