Fix template.visibilty checkbox behaviour

Prior to this commit, the default checked/unchecked values were used (i.e. "1" would be returned when checked, and "0" would be returned when unchecked). However, the box is meant to be checked when selecting 'organisationally_visible' ('for internal %{org_name} use only'), which makes the default checked/unchecked values opposite to the mapping of our enums (i.e. `{"organisationally_visible"=>0, "publicly_visible"=>1}`).

app/views/org_admin/templates/_form.html.erb

@@ -20,7 +20,10 @@
                          placement: 'right' }%>
     <div class="form-check">
       <%= f.label(:visibility) do %>
-        <%= f.check_box(:visibility, checked: f.object.organisationally_visible?) %>
+        <%= f.check_box(:visibility,
+                        { checked: f.object.organisationally_visible? },
+                        f.object.class.visibilities[:organisationally_visible],
+                        f.object.class.visibilities[:publicly_visible]) %>
 
         <%= _('for internal %{org_name} use only') % { org_name: f.object.org.name } %>
       <% end %>