fix bug in llms

Author: Liqu1d-G

lagent/llms/base_llm.py

@@ -53,7 +53,7 @@ def __call__(self, dialog) -> str:
                     if item:
                         prompt += last_sep + item
                 elif item.get('content', ''):
-                    prompt += last_sep + item.get('prompt', '')
+                    prompt += last_sep + item.get('content', '')
                 last_sep = '\n'
         return prompt