Added 'taxedPricePortions' field to CustomLineItem

We introduced the taxedPricePortions field on CustomLineItem to add additional support for Carts containing multiple Shipping Methods.

Changes:

• [API] Added the taxedPricePortions field to CustomLineItem.

• [API] Added the shippingKey field to Set CustomLineItem TaxAmount and Set CustomLineItem TaxRate update actions on Carts.

• [API] Added the shippingKey field to Set CustomLineItem TaxAmount and Set CustomLineItem TaxRate update actions on Order Edits.

• [GraphQL API] Changed the CustomLineItem type:

  • Added the taxedPricePortions field to the CustomLineItem type.

The following changes were introduced in terms of GraphQL SDL:

extend type CustomLineItem {
  taxedPricePortions: [MethodTaxedPrice!]!
}