SFTP folders with no valid samples are staged as tmp_processing instead of invalid_samples

[Shettland]

Within download module, prior to downloading anything, the module checks for some required info like sample-file relations and sample_sequencing_IDs. When a folder does not have any valid sample in its metadata during excel check for one of those reasons, the folder is not renamed to XXX_invalid_samples, and is with the tmp_processing sufix.