Fix page titles that didn’t get fixed before

Did most of this work in:
https://github.com/alphagov/notifications-admin/pull/1118

> In pages specific to a service (e.g. dashboard and sub pages) the
> title needs to distinguish which service it applies to. This is mainly
> to give context to screen reader users who could be managing multiple
> services.
>
> Implementing this uses template inheritance:
>
> `page_title` includes `per_page_title` includes `service_page_title`
>
> ‘GOV.UK Notify’ is inserted into every page title.
>
> Pages that set `service_page_title` get the service name inserted too.

app/templates/views/dashboard/all-template-statistics.html

@@ -1,7 +1,7 @@
 {% extends "withnav_template.html" %}
 
-{% block page_title %}
-  {{ current_service.name }} – GOV.UK Notify
+{% block service_page_title %}
+  {{ current_service.name }}
 {% endblock %}
 
 {% block maincolumn_content %}