Refactor export button logic in app.py: streamline the addition of portfolios to the export base by replacing the button context with a conditional check, enhancing user interaction and code clarity.

app.py

@@ -1104,10 +1104,8 @@ with tab2:
                 with download_port:
                     st.download_button(label="Download Portfolio", data=st.session_state['export_file'].to_csv(index=False), file_name="portfolio.csv", mime="text/csv")
                 with merge_port:
-                    with st.button("Add to export"):
+                    if st.button("Add to export"):
                         st.session_state['export_base'] = pd.concat([st.session_state['export_base'], st.session_state['export_file']])
-                with blank_export_col:
-                    st.button("Clear export portfolio")
             else:
                 st.error("No portfolio to download")