Define export formats model.names attribute (#9474)

ultralytics/engine/model.py

@@ -735,7 +735,10 @@ class Model(nn.Module):
 
         if hasattr(self.model, "names"):
             return check_class_names(self.model.names)
-        elif self.predictor:
+        else:
+            if not self.predictor:  # export formats will not have predictor defined until predict() is called
+                self.predictor = self._smart_load("predictor")(overrides=self.overrides, _callbacks=self.callbacks)
+                self.predictor.setup_model(model=self.model, verbose=False)
             return self.predictor.model.names
 
     @property