Change page <title> on check page

It was no longer accurate.

app/main/views/send.py

@@ -256,7 +256,6 @@ def check_messages(service_id, template_type, upload_id):
         recipients=recipients,
         first_recipient=first_recipient,
         template=template,
-        page_heading=get_page_headings(template.template_type),
         errors=recipients.has_errors,
         row_errors=get_errors_for_csv(recipients, template.template_type),
         count_of_recipients=session['upload_data']['notification_count'],

app/templates/views/check.html

@@ -10,7 +10,7 @@
 {% from "components/message-count-label.html" import message_count_label %}
 
 {% block page_title %}
-  {{ page_heading if errors else "Check and confirm" }} – GOV.UK Notify
+  {{ "Error" if errors else "Check and confirm" }} – GOV.UK Notify
 {% endblock %}
 
 {% block maincolumn_content %}