fix(export_model): fix export_model.py python path

1.fix python path to paddlenlp project

llm/predict/export_model.py

@@ -18,8 +18,8 @@
 
 import paddle
 from paddle.distributed import fleet
-from predict.predictor import ModelArgument, PredictorArgument, create_predictor
 
+from llm.predict.predictor import ModelArgument, PredictorArgument, create_predictor
 from paddlenlp.trainer import PdArgumentParser
 from paddlenlp.trl import llm_utils