ShopperBaskets `addItemToBasket` has illegal body type since v4

[blurrah]

The addItemToBasket function has an illegal body type body: Array<ProductItem> & CustomRequestBody which cannot overlap as one is an array and the other an object.

It should be body: Array<ProductItem & CustomRequestBody> most likely.

[loren138]

There are quite a few types with this (update items, add items, etc)
I ended up patching the type file locally since I couldn't find another way to satisfy typescript, but would love a fix

(ProductItems already supports any key so I'm not sure custom request body needs to be added there necessarily)