Didn't work with non-dicom data

[pieper]

When I tried running the module on a CT scan from Slicer's SampleData module it failed with this message in the console. It would be better to give a dialog warning that DICOM data is required and then fail gracefully. (or maybe it can work on non-DICOM data?).

Creating SAM predictor ... weights not found
Downloading SAM weights ... Done
Creating SAM predictor ... Done
Traceback (most recent call last):
  File "/home/exouser/Downloads/Slicer-5.3.0-2023-07-08-linux-amd64/slicer.org/Extensions-31860/TomoSAM/lib/Slicer-5.3/qt-scripted-modules/tomosam.py", line 492, in onPushEmbeddingsCreate
    instanceUIDs = volume_node.GetAttribute("DICOM.instanceUIDs").split()
AttributeError: 'NoneType' object has no attribute 'split'