Order confirmation email template with line item properties

order_confirmation_template.liquid

{% unless line.properties == empty %}
<ul style="list-style-type: none; padding: 0;">
  {% for property in line.properties %}
  <li><span class="order-list__item-variant">{{ property.first }}: {{ property.last }}</span></li>
  {% endfor %}
</ul>
{% endunless %}