fix: add use_default_token for qianwen (#600)

Author: lwj2015

kubechat/llm/qianwen.py

@@ -21,6 +21,8 @@ def __init__(self, **kwargs):
         if not self.api_key:
             raise LLMConfigError("Please specify the API KEY")
 
+        self.use_default_token = not kwargs.get("api_key", "")
+
     @staticmethod
     def provide_default_token():
         return bool(os.environ.get("QIANWEN_API_KEY", ""))