Handle Unknown Folder in prepareAssetListingForGrid

[cancan101]

This line can return null:

admin-ui-classic-bundle/src/Helper/GridHelperService.php

Line 732 in 4511150

$folder = Model\Asset::getById((int) $allParams['folderId']);

leading to error here:

admin-ui-classic-bundle/src/Helper/GridHelperService.php

Line 767 in 4511150

$conditionFilters[] = 'path LIKE ' . ($folder->getRealFullPath() === '/' ? "'/%'" : $list->quote($list->escapeLike($folder->getRealFullPath()) . '/%'));

Call to a member function getRealFullPath() on null

I assume this is coming from a race when deleting / renaming folders.