fix: Correct incomplete if statement in portfolio value section

src/streamlit_app.py

@@ -648,6 +648,8 @@ def trading_system_page():
             st.metric("Current Portfolio Value", f"${portfolio_data['total_value']:,.2f}")
             st.metric("Cash Balance", f"${portfolio_data['cash_balance']:,.2f}")
             st.text(f"Last Updated: {portfolio_data['date']}")
+        else:
+            st.info("No portfolio value data found")
         
         # Update portfolio value form
         with st.expander("Update Portfolio Value"):