**What**
Resolve potential discrepency between what is calculated in the `createFromCart` and the cart/order totals calculation.
When the giftCard is taxable then the following calculation is applied
```ts
cart.subtotal + cart.shipping_total - cart.discount_total
```
otherwise
```ts
cart.subtotal +
cart.shipping_total +
cart.tax_total -
cart.discount_total
```
Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>