Don’t treat letters as a special case

This conditional comes from before we launched the letters feature.
Since we were only giving the letters permission to teams that we were
inviting, we didn’t want to confuse new users by mentioning letters.

Nowadays all new services will have the letters permission, so this
check is redundant.

app/templates/views/templates/choose.html

@@ -31,12 +31,7 @@
        {% if current_service.has_permission('broadcast') %}
           prepare a broadcast
        {%- else %}
-          send
-          {% if 'letter' in current_service.permissions %}
-            emails, text messages or letters
-          {%- else -%}
-            emails or text messages
-          {%- endif %}
+          send emails, text messages or letters
        {%- endif %}.
      </p>