Fix preset display_snippets not rendered in group about page

[Skitionek]

Use _expanded_schema fields when rendering group template.
Without the change presets were not loaded therefore wrong display_snippets were rendered.

[Skitionek]

Workaround:
Overwrite templates to replace c.scheming_fields ref with h.scheming_get_organization_schema(group_type)['fields'].

ckanext/scheming/templates/scheming/organization/about.html

{% extends "organization/about.html" %}

{% if group_dict is not defined%}
    {% set group_dict = c.group_dict %}
{% endif %}

{% block primary_content_inner %}
<dl>
+ {%- set scheming_fields = h.scheming_get_organization_schema(group_type)['fields'] -%}
+ {% for f in scheming_fields %}
- {% for f in c.scheming_fields %}
<dt>{{ h.scheming_language_text(f.label) }}:</dt>
<dd>{{ group_dict[f.field_name] or ("&nbsp;"|safe) }}</dd>
{% endfor %}
</dl>
{% endblock %}