fix: tokenizer chat template sys msg

tokenizer_config.json

@@ -1744,7 +1744,7 @@
     "<end_of_turn>"
   ],
   "bos_token": "<bos>",
-  "chat_template": "{% if messages[0]['role'] == 'system' %}{% set system_message = messages[0]['content'] %}{% endif %}{{ '<bos>' + system_message }}{% for message in messages %}{% set content = message['content'] %}{% if message['role'] == 'user' %}{{ '<start_of_turn>user\\n' + content + '<end_of_turn>\\n<start_of_turn>model\\n' }}{% elif message['role'] == 'assistant' %}{{ content + '<end_of_turn>\\n' }}{% endif %}{% endfor %}",
+  "chat_template": "{{ '<bos>' }}{% if messages[0]['role'] == 'system' %}{% set system_message = messages[0]['content'] %}{{ system_message }}{% endif %}{% for message in messages %}{% set content = message['content'] %}{% if message['role'] == 'user' %}{{ '<start_of_turn>user\\n' + content + '<end_of_turn>\\n<start_of_turn>model\\n' }}{% elif message['role'] == 'assistant' %}{{ content + '<end_of_turn>\\n' }}{% endif %}{% endfor %}",
   "clean_up_tokenization_spaces": false,
   "eos_token": "<eos>",
   "model_max_length": 1000000000000000019884624838656,