Update key_request.py

Added place where old generated keys are stored as to no lose them.

key_request.py

@@ -143,6 +143,10 @@ def show():
         on_click=button,
     )
 
+    if 'last_key' not in st.session_state:
+        st.session_state.last_key = "No generated keys!"
+    st.success("Last key you generated (may not still be valid): "+st.session_state.last_key)
+    
     if st.session_state.button_clicked:
         display_text = st.empty()
         ctime = get_current_time()
@@ -163,7 +167,8 @@ def show():
 
             display_text.success(
                 "Access key: " + access_key
-            )  # change placeholder to access_key
+            )
+            st.session_state.last_key = access_key
             update_variable(microscope, ctime)
 
         else: