Revert "Remove unnecessary scrollBehavior function in router."

This reverts commit 275ccbc547.

src/router/router.js

@@ -75,6 +75,9 @@ const routes = [
 const router = createRouter({
     history: createWebHistory(),
     routes,
+    scrollBehavior: function (_to, _from, savedPosition) {
+        return savedPosition ? savedPosition : window.scrollTo(0, 0);
+    },
 });
 
 export default router;