ToDo::buildFilesBlock

private function buildFilesBlock(): ?ContentBlock
{
	$storageFiles = $this->fetchStorageFiles();
	if (empty($storageFiles))
	{
		return null;
	}

	$files = $this->prepareFiles($storageFiles);

	$fileListBlock = (new FileList())
		->setTitle(Loc::getMessage('CRM_TIMELINE_ITEM_TODO_FILES'))
		->setFiles($files);

	if ($this->isScheduled() && $this->hasUpdatePermission())
	{
		$fileListBlock->setUpdateParams([
			'type' => $this->getType(),
			'entityTypeId' => CCrmOwnerType::Activity,
			'entityId' => $this->getActivityId(),
			'files' => array_column($storageFiles, 'FILE_ID'),
			'ownerTypeId' =>  $this->getContext()->getIdentifier()->getEntityTypeId(),
			'ownerId' => $this->getContext()->getIdentifier()->getEntityId(),
		]);
	}

	return $fileListBlock;
}