PrototypeItem::deleteUserFieldValues

static function deleteUserFieldValues(int $id): MainResult
{
	/** @var Item $item */
	$item = static::getById($id)->fetchObject();
	$userTypeManager = UserFieldHelper::getInstance()->getManager();
	if ($userTypeManager instanceof CUserTypeManager)
	{
		$userFields = $userTypeManager->GetUserFields(static::getItemUserFieldEntityId());
		foreach($userFields as $userField)
		{
			$item->set($userField['FIELD_NAME'], null);
		}
	}

	return Driver::getInstance()->getFactory()->getUpdateCommand($item)->run();
}