Persist actions log time display settings in localStorage (#36623)

Persist the two boolean settings in the actions log into `localStorage`
so that they are remembered across page reloads.

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

web_src/js/modules/user-settings.ts

@@ -58,8 +58,8 @@ export const localUserSettings = {
   getJsonObject: <T extends Record<string, any>>(key: string, def: T): T => {
     const value = getLocalStorageUserSetting(key);
     try {
-      const decoded = value !== null ? JSON.parse(value) : def;
-      return decoded ?? def;
+      const decoded = value !== null ? JSON.parse(value) : null;
+      return {...def, ...decoded};
     } catch (e) {
       console.error(`Unable to parse JSON value for local user settings ${key}=${value}`, e);
     }