Update app.py

app.py

@@ -143,6 +143,7 @@ def launch_bot():
 
             if st.button("Opt out"):
                 st.session_state.cookies['opt-out'] = 'true'
+                st.session_state.cookies.save()
                 st.rerun()
 
     st.markdown(f"<center> <h2> Vectara AI Assistant: {cfg.title} </h2> </center>", unsafe_allow_html=True)