[UX] tab5_sensitivity.py: British spelling (optimization -> optimisation)

tabs/tab5_sensitivity.py

@@ -275,7 +275,7 @@ def show_bottleneck_analysis():
     """
     latest = st.session_state.get("latest_result")
     if not latest:
-        st.info("Run the optimization first (Portfolio generation tab) to see the bottleneck analysis.", icon=":material/info:")
+        st.info("Run the optimisation first (Portfolio generation tab) to see the bottleneck analysis.", icon=":material/info:")
         return
 
     st.markdown('<p class="crra-sub-heading">Resource sensitivity</p>', unsafe_allow_html=True)