Fix `subscription_available_plans` about team plan

What does this MR do and why?

Issue: https://jihulab.com/gitlab-cn/gitlab/-/issues/4411

What

解决这样一个问题：在 SaaS 购买 Plan 时未显示 Team Plan：

Why

之前在移除 FF jh_saas_team_plan 时，把代码中的 disabled 当做了 enabled 处理：!2636 (d75863fb)

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