Refactor `prepare_submission_data` in `hf_submission_api.py` to fix answer extraction and improve payload handling

src/gaia_solving_agent/hf_submission_api.py

@@ -150,19 +150,20 @@ async def run_agent(agent, questions_data, additional_files):
 
 def prepare_submission_data(username:str, agent_code: str, answers_payload: list[dict]):
     def extract_answer(answer: str) -> str | int:
-        pattern = r"FINAL ANSWER:\s*(.*)"
+        pattern = r"FINAL ANSWER:\s*(.*)\s+"
         search = re.search(pattern, answer)
-        extracted_answer = search.group(1) if search else ""
+        extracted_answer = search.group(1).strip() if search else ""
         try:
             return eval(extracted_answer)
         except:
             return extracted_answer
 
-    for answer in answers_payload:
+    _answers_payload = [{k:v for k,v in answer.items()} for answer in answers_payload]
+    for answer in _answers_payload:
         answer["submitted_answer"] = extract_answer(str(answer["submitted_answer"]))
 
-    submission_data = {"username": username.strip(), "agent_code": agent_code, "answers": answers_payload}
-    status_update = f"Agent finished. Preparing {len(answers_payload)} answers to submit for user '{username}'..."
+    submission_data = {"username": username.strip(), "agent_code": agent_code, "answers": _answers_payload}
+    status_update = f"Agent finished. Preparing {len(_answers_payload)} answers to submit for user '{username}'..."
     print(status_update)
     return submission_data