ENH: update ScalarVolumePlugin to not attempt loading DICOM SEG
Created by: fedorov
DICOM Segmentation IOD cannot be loaded using any of the loaders included in the core Slicer application. Do not attempt to load it and mislead the user with the failure message. Log error to recommend the user should install QuantitativeReporting extension that can properly handle this type of object.
For the reference, see discussion in https://discourse.slicer.org/t/segmentation-storage-1-2-840-10008-5-1-4-1-1-66-4/4274/12?u=fedorov.