Customise download page if agreement signed

If the user’s organisation has already signed the agreement we shouldn’t
give them the instructions for how to sign it.

app/main/views/agreement.py

@@ -20,6 +20,13 @@ def agreement():
             navigation_links=features_nav(),
         )
 
+    if agreement_info.agreement_signed:
+        return render_template(
+            'views/agreement-signed.html',
+            owner=agreement_info.owner,
+            navigation_links=features_nav(),
+        )
+
     return render_template(
         'views/agreement.html',
         owner=agreement_info.owner,

app/templates/views/agreement-signed.html

@@ -0,0 +1,33 @@
+{% extends "withoutnav_template.html" %}
+{% from "components/sub-navigation.html" import sub_navigation %}
+
+{% block per_page_title %}
+  Download the GOV.UK Notify data sharing and financial agreement
+{% endblock %}
+
+{% block maincolumn_content %}
+
+<div class="grid-row">
+  <div class="column-one-third">
+    {{ sub_navigation(navigation_links) }}
+  </div>
+  <div class="column-two-thirds">
+
+    <h1 class="heading-large">
+      Download the GOV.UK Notify data sharing and financial agreement
+    </h1>
+
+    <p>
+      Your organisation ({{ owner }}) has already accepted the GOV.UK
+      Notify data sharing and financial agreement.
+    </p>
+    <p>
+      If you need to you can <a href="{{ url_for('main.download_agreement') }}">download a copy here</a>.
+    </p>
+    <p>
+      The agreement contains commercially sensitive information, so don’t share it more widely than you need to.
+    </p>
+  </div>
+</div>
+
+{% endblock %}

tests/app/main/views/test_agreement.py

@@ -21,7 +21,6 @@ class _MockS3Object():
         'test@cabinet-office.gov.uk',
         [
             partial(url_for, 'main.download_agreement'),
-            lambda: 'mailto:notify-support@digital.cabinet-office.gov.uk',
         ]
     ),
     (