Add warning to catch torch import mistakes. (Comfy-Org#8852)

Author: comfyanonymous

main.py

@@ -127,6 +127,9 @@ def execute_script(script_path):
 
     import cuda_malloc
 
+if 'torch' in sys.modules:
+    logging.warning("WARNING: Potential Error in code: Torch already imported, torch should never be imported before this point.")
+
 import comfy.utils
 
 import execution