fix(admin): 修复共富用户等级更新参数验证问题

- 修改 partner_level 参数验证逻辑，从 empty 检查改为 isset 检查
- 防止当 partner_level 为 0 时的误判情况
- 确保参数验证逻辑符合业务需求

app/controller/admin/system/sharedProsperity/SharedProsperityUser.php

@@ -31,7 +31,7 @@ class SharedProsperityUser
         /** @var SharedProsperityUserRepository $repository */
         $repository = app()->make(SharedProsperityUserRepository::class);
         $params = app('request')->params(['user_id', 'partner_level', 'remark']);
-        if (empty($params['user_id']) || empty($params['partner_level']) || empty($params['remark'])) {
+        if (empty($params['user_id']) || !isset($params['partner_level']) || empty($params['remark'])) {
             return app('json')->fail('参数错误');
         }
         $res = $repository->updateLevel($params['user_id'], $params['partner_level'], request()->adminId(), $params['remark']);