Scanning newly created folders is doing too much work

[CarlSchwan]

Line	Method
3rdparty/doctrine/dbal/src/Connection.php 1149	OC\DB\BacktraceDebugStack->startQuery
lib/private/DB/Connection.php 294	Doctrine\DBAL\Connection->executeStatement
3rdparty/doctrine/dbal/src/Query/QueryBuilder.php 354	OC\DB\Connection->executeStatement
lib/private/DB/QueryBuilder/QueryBuilder.php 281	Doctrine\DBAL\Query\QueryBuilder->execute
lib/private/Files/Cache/Cache.php 382	OC\DB\QueryBuilder\QueryBuilder->execute
lib/private/Files/Cache/Scanner.php 401	OC\Files\Cache\Cache->update
lib/private/Files/Cache/Scanner.php 342	OC\Files\Cache\Scanner->scanChildren
lib/private/Files/Cache/LocalRootScanner.php 39	OC\Files\Cache\Scanner->scan
lib/private/Files/Cache/Updater.php 125	OC\Files\Cache\LocalRootScanner->scan
lib/private/Files/View.php 327	OC\Files\Cache\Updater->update
lib/private/Files/View.php 1191	OC\Files\View->writeUpdate
lib/private/Files/View.php 275	OC\Files\View->basicOperation
lib/private/Files/Node/Folder.php 163	OC\Files\View->mkdir
lib/private/Files/AppData/AppData.php 147	OC\Files\Node\Folder->newFolder
lib/private/Preview/Storage/Root.php 74	OC\Files\AppData\AppData->newFolder
lib/private/Preview/Generator.php 578	OC\Preview\Storage\Root->newFolder
lib/private/Preview/Generator.php 134	OC\Preview\Generator->getPreviewFolder
lib/private/Preview/Generator.php 111	OC\Preview\Generator->generatePreviews
lib/private/PreviewManager.php 212	OC\Preview\Generator->getPreview
core/Controller/PreviewController.php 133	OC\PreviewManager->getPreview
core/Controller/PreviewController.php 112	OC\Core\Controller\PreviewController->fetchPreview
lib/private/AppFramework/Http/Dispatcher.php 225	OC\Core\Controller\PreviewController->getPreviewByFileId
lib/private/AppFramework/Http/Dispatcher.php 133	OC\AppFramework\Http\Dispatcher->executeController
lib/private/AppFramework/App.php 172	OC\AppFramework\Http\Dispatcher->dispatch
lib/private/Route/Router.php 298	OC\AppFramework\App::main
lib/base.php 1033	OC\Route\Router->match
index.php 36	OC::handleRequest

partial fix: #33551

[CarlSchwan]

Maybe better fix #33612?