fix: better handle search query list in case some llms respond with extra words

[benhaotang]

rewrite this part to

   if response:
        cleaned = response.strip()
        if cleaned == "<done>":
            return "<done>"
        # First, try to directly evaluate the cleaned string
        try:
            new_queries = ast.literal_eval(cleaned)
            if isinstance(new_queries, list):
                return new_queries
        except Exception as e:
            # Direct evaluation failed; try to extract the list part from the string.
            match = re.search(r'(\[.*\])', cleaned, re.DOTALL)
            if match:
                list_str = match.group(1)
                try:
                    new_queries = ast.literal_eval(list_str)
                    if isinstance(new_queries, list):
                        return new_queries
                except Exception as e_inner:
                    print("Error parsing extracted list:", e_inner, "\nExtracted text:", list_str)
                    return []
            print("Error parsing new search queries:", e, "\nResponse:", response)
            return []
    return []

so that is llms return:

• '<done>': still finish
• only list: still search
• list with explanations: remove explanations then search