Remove unclaimed 'warnings' package from requirements.txt; use Python stdlib warnings module

end-to-end-use-cases/NotebookLlama/requirements.txt

@@ -10,6 +10,3 @@ tqdm>=4.66.0
 # Optional but recommended
 jupyter>=1.0.0
 ipykernel>=6.0.0
-
-# Warning handling
-warnings>=0.1.0