fix qna_answer integer issue

qna_prompting.py

@@ -114,8 +114,11 @@ def evaluate_qna_answer(user_selected_answer: str) -> str:
         question_id = st.session_state.question_id
         qna_answer  = st.session_state.qna_answer
         reasons     = st.session_state.reasons
+
+        ### convert to numeric type
+        qna_answer  = int(qna_answer)
         
-        qna_answer_alphabet = num_mapping.get(int(qna_answer), "ERROR")
+        qna_answer_alphabet = num_mapping.get(qna_answer, "ERROR")
 
         con = sqlite3.connect(db_path)
         cur = con.cursor()