Added predicate builder to Shipping Methods

You can now create, edit, and view predicates for Shipping Methods using the predicate builder. This feature lets you create complex predicates and conditional rules through a user-friendly interface without the need to write predicate syntax. Using the predicate builder, you can create predicates that apply only to specific Carts, or to all Carts. Previously, you defined Shipping Method predicates through an input field.

The Shipping Methods predicate builder is similar to the one found within the Discounts area of the Merchant Center.