Move ‘send test’ link back to template page

This changes it back to how it was when we first introduced this
feature:
https://github.com/alphagov/notifications-admin/pull/181

It’s kind of lost on the page where you upload a file, which is a shame
because it’s a good teaching aid.

app/templates/views/send-test.html

@@ -14,7 +14,7 @@
   {% if request.args['help'] %}
     <h1 class="heading-large">Example text message</h1>
   {% else %}
-    <h1 class="heading-large">Send a test</h1>
+    <h1 class="heading-large">Send yourself a test</h1>
   {% endif %}
 
   {% if 'sms' == template.template_type %}