Convert radios on set {email|sms|letters} pages

All use the ServiceSwitchChannelForm.enabled
field, inherited from ServiceOnOffSettingForm.

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

@@ -2,7 +2,6 @@
 {% from "components/form.html" import form_wrapper %}
 {% from "components/page-header.html" import page_header %}
 {% from "components/page-footer.html" import page_footer %}
-{% from "components/radios.html" import radios %}
 
 {% block service_page_title %}
   Send emails
@@ -20,7 +19,7 @@
         It’s free to send emails through GOV.UK Notify.
       </p>
       {% call form_wrapper() %}
-        {{ radios(form.enabled) }}
+        {{ form.enabled }}
         {{ page_footer('Save') }}
       {% endcall %}
     </div>

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

@@ -1,5 +1,4 @@
 {% extends "withnav_template.html" %}
-{% from "components/radios.html" import radios %}
 {% from "components/page-header.html" import page_header %}
 {% from "components/page-footer.html" import page_footer %}
 {% from "components/form.html" import form_wrapper %}
@@ -24,7 +23,7 @@
         of rates.
       </p>
       {% call form_wrapper() %}
-        {{ radios(form.enabled) }}
+        {{ form.enabled }}
         {{ page_footer('Save') }}
       {% endcall %}
     </div>

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

@@ -2,7 +2,6 @@
 {% from "components/form.html" import form_wrapper %}
 {% from "components/page-header.html" import page_header %}
 {% from "components/page-footer.html" import page_footer %}
-{% from "components/radios.html" import radios %}
 
 {% block service_page_title %}
   Send text messages
@@ -29,7 +28,7 @@
         See <a class="govuk-link govuk-link--no-visited-state" href="{{ url_for(".pricing", _anchor="letters") }}">pricing</a> for more details.
       </p>
       {% call form_wrapper() %}
-        {{ radios(form.enabled) }}
+        {{ form.enabled }}
         {{ page_footer('Save') }}
       {% endcall %}
     </div>