[DAR-4137][External] Do not push files in root of pushed directories to a . directory when preserve_folders=True

[JBWilkie]

Problem

Items in the root of a folder being pushed are currently uploaded to a . folder, instead of the actual dataset root itself

Solution

When uploading files while preserving the local directory structure, place items in the root of target directories into the dataset root instead of a . directory

Changelog

Fixed minor bug when uploading files to the root of a dataset folder when preserving the local directory structure

[linear]

DAR-4137 BUG: Pushing items with `--preserve-folders` uploads items in the root to a `.` folder