Update app.py

Fix variable name error.

app.py

@@ -91,7 +91,7 @@ if txt:
 ## Moderation ##
 if st.session_state.chatgpt:
     st.markdown("##### :blue[Content moderation: ]")
-    st.plotly_chart(fig)    
+    st.plotly_chart(fig_r)    
 
 ## Cost of summarisation ## 
     st.text("Total cost for this query: " + "$" + str(total_cost))