feat: return import_failed from init_extra_nodes function (Comfy-Org#4694)

Author: badayvedat

nodes.py

@@ -2129,3 +2129,5 @@ def init_extra_nodes(init_custom_nodes=True):
         else:
             logging.warning("Please do a: pip install -r requirements.txt")
         logging.warning("")
+    
+    return import_failed