etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Facebook\BusinessExtension\Helper\ServerSideHelper">
      <plugin name="capi_events_modifier_plugin" type="Facebook\BusinessExtension\Plugin\CAPIEventsModifierPlugin" sortOrder="1" disabled="false" />
    </type>
</config>