{# @var ea \EasyCorp\Bundle\EasyAdminBundle\Context\AdminContext #}
{# @var field \EasyCorp\Bundle\EasyAdminBundle\Dto\FieldDto #}
{# @var entity \EasyCorp\Bundle\EasyAdminBundle\Dto\EntityDto #}

{% set vendor = null %}
{% for singleOrderItem in entity.instance.orderItems %}
    {% set vendor = singleOrderItem.product.vendor %}
{% endfor %}

<span class="badge badge-primary" >{{vendor}}</span>