fix clip extra when QAT export model (#38323)

Author: yghstill

python/paddle/fluid/contrib/slim/quantization/imperative/qat.py

@@ -506,7 +506,7 @@ def save_quantized_model(self, model, path, input_spec=None, **config):
             main_program=infer_program.clone(),
             model_filename=model_filename,
             params_filename=params_filename,
-            clip_extra=True)
+            clip_extra=False)
 
         if is_dynamic_mode:
             paddle.disable_static()