Fix another non reactive property warning

I waited for the PR check to pass first, but it failed to catch this,
presumably as newly-added files don't trigger the existing checks to
re-run.

ts/routes/deck-options/EasyDays.svelte

@@ -15,6 +15,7 @@ License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
     const config = state.currentConfig;
     const defaults = state.defaults;
 
+    // svelte-ignore reactive_declaration_non_reactive_property
     $: if ($config.easyDaysPercentages.length !== 7) {
         $config.easyDaysPercentages = defaults.easyDaysPercentages;
     }