Restore correct spacing on templates page

During the move to GOV.UK Frontend checkboxes our template list has
started to be wrapped in a `<div>` with the `govuk-form-group` class.

This adds extra spacing, like you’d want in a regular transaction
service which might have multiple sets of form controls on a single
page.

It isn’t appropriate on our templates page, because there should be a
consistent rhythm where the space between each checkboxes is the same as
the space between the search box and the first checkbox, to the last
checkbox and the buttons. Not having this space is also consistent with
other pages with sticky grey buttons, eg the team members page.

This commit also fixes a typo in the name of one of the classes used to
control spacing between the checkboxes and search bar.

app/templates/views/templates/_template_list.html

@@ -23,7 +23,7 @@
     {% endif %}
   </p>
 {% else %}
-  <nav id="template-list" class="{{ 'govuk-!-margin-top-1' if (not show_template_nav and not show_search_box) else 'govuk-!margin-top-6' }}">
+  <nav id="template-list" class="{{ 'govuk-!-margin-top-1' if (not show_template_nav and not show_search_box) else 'govuk-!-margin-top-6' }}">
     {% set checkboxes_data = [] %}
 
     {% for item in template_list %}
@@ -85,7 +85,10 @@
     {% endfor %}
 
     {% if current_user.has_permissions('manage_templates') %}
-      {{ templates_and_folders_form.templates_and_folders(param_extensions={ "items": checkboxes_data }) }}
+      {{ templates_and_folders_form.templates_and_folders(param_extensions={
+        "items": checkboxes_data,
+        "formGroup": False
+      }) }}
     {% endif %}
   </nav>
 {% endif %}