Changing "Scale results per page to window height" has no effect until page refresh

If you change the value of `Scale results per page to window height` in your preferences and save, it has no effect until you refresh the page or force a navigation to a new page. I had expected it to kick-in immediately after saving the preferences, rather than some almost-random time later

No files or tests are named. Start by locating the `Scale results per page to window height` preference and its save handler, reproduce the delayed update, and trace the refresh or navigation path that applies it. Done means saving the preference updates the results-per-page behavior immediately without a refresh or navigation.

Written by the indexing model from the issue text.