Fix VAT info is not properly updated when changing plan without reloading.
I removed `setPlan` and created a new function: `updatePlan`. In the new function, I call the recurly function directly and the tracking code. This way, we can be sure that changing plan won't call useLayoutEffect.
Also, remove unused `useState` on the `planCode`
GitOrigin-RevId: 0d6d9fac32c15dcf13e35cf9cd9161aa07581938