Parent folder is duplicated in elements.json for each file on the file import

The parent folder created by the backend is added once for each DataFile processed by the files import. This causes it to be duplicated in elements.json and causes the element count at the end of the import to be incorrect; for example, importing five images will cause a log of 10 created elements, where there actually only have been five new elements, and the folder is added 5 times to elements.json