Draft: Remove the JH overriding code for the purchasing flows

What does this MR do and why?

Remove the JH overriding code for the purchasing flows

How to set up and validate locally

1. Checkout to branch feat/enable-new-purchase-flows

   git pull
   git checkout feat/enable-new-purchase-flows

Related CustomerDot MR

https://jihulab.com/gitlab-cn/internal/customers-jihulab-com/-/merge_requests/253

MR acceptance checklist

• When upgrading from Free/Trial Plan to Premium/Ultimate, it will jump to a new process
• When purchasing CI minutes, it will jump to a new process
• When purchasing Storage limit, it will jump to a new process