MessageUserType::onDelete

static function onDelete($userField, $messageId)
{
	$result = static::deleteList([
		'=MESSAGE_ID' => $messageId,
		'=ENTITY_UF_ID' => $userField['ID'],
		'=ENTITY_TYPE' => $userField['ENTITY_ID'],
		'=ENTITY_ID' => $userField['ENTITY_VALUE_ID'],
	]);
}