Fix the sync status push for parent directories #4682

Fix the sync status push for parent directories #4682

As before, we rely on metadata-update SyncFileItem entries for parent
directories to notify us that a directory contains files to propagate,
and to know when all children were propagated through its itemCompleted
signal.

Those metadata SyncFileItems however have a None direction and we need
to add a explicit directory check to show them as Sync.
This fix also handles new files as well as existing ones, so no need
to keep a separate logic for new files.