[bugfix] fix from_dict (#5506)

Author: hjh0119

swift/trainers/rlhf_trainer/grpo_trainer.py

@@ -1229,7 +1229,7 @@ def _apply_chat_template_to_messages_list(self, messages_list: InputsType):
         prompts_text = []
         for messages in messages_list:
             InferRequest.remove_response(messages)
-            template_inputs, _ = StdTemplateInputs.from_dict({'messages': messages})
+            template_inputs = StdTemplateInputs.from_dict({'messages': messages})
             res = self.template.encode(template_inputs)
             prompts_text.append(self.template.safe_decode(res['input_ids']))
         return prompts_text