fix(coupon): correct validation logic for unavailable dates

- Fix incorrect comment logic in validateCouponUnavailableDate method
- Return failure when unavaiLableDate is empty instead of success
- Ensure proper date validation for coupon availability checks

alien-store-platform/src/main/java/shop/alien/storeplatform/service/impl/CouponManageServiceImpl.java

@@ -235,9 +235,9 @@ public class CouponManageServiceImpl implements CouponManageService {
     private R<String> validateCouponUnavailableDate(LifeCoupon lifeCoupon) {
         // 限制日期: 1234567;节日id
         if ("2".equals(lifeCoupon.getUnusedType())) {
-//            if (StringUtils.isEmpty(lifeCoupon.getUnavaiLableDate())) {
-//                return R.success("无不可用日期限制");
-//            }
+            if (StringUtils.isEmpty(lifeCoupon.getUnavaiLableDate())) {
+                return R.fail("未查到可用日期限制");
+            }
 
             LocalDate nowDate = LocalDate.now();
             DayOfWeek dayOfWeek = nowDate.getDayOfWeek();