look at the right var for NIM name checking (NVIDIA#871)

should be `self.name` not `name`

garak/generators/nim.py

@@ -92,7 +92,7 @@ def _call_model(
 
     def __init__(self, name="", config_root=_config):
         super().__init__(name, config_root=config_root)
-        if "/" not in name:
+        if "/" not in self.name:
             msg = "❓ Is this a valid NIM name? expected a slash-formatted name, e.g. 'org/model'"
             logging.info(msg)
             print(msg)