fix(GameShield): 修复创建后端配置时的设备数量限制和 SDK 参数

- 添加获取配置限制的逻辑，确保在线设备数量限制正确
- 将 max_device_count 设置为从配置中获取的实际值
- 移除 sdk_args 的空字符串值，避免潜在错误

internal/service/gameshieldbackend.go

@@ -119,14 +119,18 @@ func (s *gameShieldBackendService) GameShieldBackend(ctx context.Context, req *v
 	if err != nil {
 		return "", 0, err
 	}
+	configCount, err := s.hostService.GetGameShieldConfig(ctx, req.HostId)
+	if err != nil {
+		return "", 0, fmt.Errorf("获取配置限制失败: %w", err)
+	}
 	formData := map[string]interface{}{
 		"app_name":             require.DunName,
 		"gateway_group_id":     4,
 		"backend":              require.Backend,
 		"rule_id":              require.RuleId,
 		"expired_at":           require.ExpiredAt,
-		"max_device_count":     "max-bandwidth 1000K",
-		"sdk_args":             "",
+		"max_device_count":     configCount.OnlineDevicesCount,
+		"sdk_args":             "max-bandwidth 1000K",
 		"__go_admin_previous_": tokens["previous"],
 		"__go_admin_t_":        tokens["t"],
 	}