refactor: drop order quick shortcuts, keep My Orders tile only

Per feedback the 待支付/售后 shortcut row is not wanted. Remove the nested
quick grid, delete the now-orphaned sidebar-orders renderer, and strip its
uc-order-grid CSS. 我的订单 remains a single tile in the 我的服务 grid.

inc/helpers/user-center-renderers/sidebar-nav.php

@@ -79,9 +79,6 @@ $render_grid = static function (array $items): void {
 <div class="uc-sidebar__section">
 	<div class="uc-sidebar__heading"><span><?php esc_html_e('我的服务', 'aksrt'); ?></span></div>
 	<?php $render_grid($services); ?>
-	<?php if ($orders_url !== '') : ?>
-		<?php require __DIR__ . '/sidebar-orders.php'; ?>
-	<?php endif; ?>
 </div>
 <?php endif; ?>