Landing::clearFolderIndex

public function clearFolderIndex(): void
{
	if ($this->folderId)
	{
		$resFolder = Folder::getList([
			'select' => [
				'ID'
			],
			'filter' => [
				'ID' => $this->folderId,
				'INDEX_ID' => $this->id
			]
		]);
		if ($resFolder->fetch())
		{
			Folder::update($this->folderId, [
				'INDEX_ID' => null
			]);
		}
	}
}