[MINOR] Update library versions for scuro

This commit update the Python Libraries, to allow slightly older versions of
pytorch and torch vision, while removing nltk as a dependency.

Closes #2224

Author: christinadionysio

src/main/python/systemds/__init__.py

@@ -26,14 +26,13 @@
 __all__ = ["context", "operator", "examples"]
 
 required_packages = [
-    ("torch", "2.5.1"),
-    ("torchvision", "0.20.1"),
+    ("torch", "2.4.1"),
+    ("torchvision", "0.19.1"),
     ("librosa", "0.10.2"),
     ("opencv-python", "4.10.0.84"),
     ("opt-einsum", "3.3.0"),
     ("h5py", "3.11.0"),
     ("transformers", "4.46.3"),
-    ("nltk", "3.9.1"),
     ("gensim", "4.3.3"),
 ]