Allow excluding services from live services count

Adds a front end for:
https://github.com/alphagov/notifications-api/pull/2417

> Sometimes we have to make a few services for what really is one
> service, for example GOV.UK Pay and GOV.UK Pay Direct Debit. We also
> have our own test services which aren’t included in the count of live
> services. We currently count these as one service by not including
> them in the beta partners spreadsheet.

app/templates/views/service-settings/set-service-setting.html

@@ -4,7 +4,7 @@
 {% from "components/form.html" import form_wrapper %}
 
 {% block service_page_title %}
-  Send letters
+  {{ title }}
 {% endblock %}
 
 {% block maincolumn_content %}