feat: Search by billing_address and shipping_address on Order model (#12814)

* feat: Search by billing_address and shipping_address on Order model

**What**
Added `.searchable()` method to the `shipping_address` and `billing_address` relationships in the `Order` model, enabling search functionality.

**Why**
Previously searching via `shipping_address` and `billing_address` was not supported, limiting the ability to find orders based on shipping or billing address information.

Resolves SUP-1838

* Update integration tests to include billing_address and non-existing addresses.

packages/modules/order/src/models/order.ts

@@ -27,12 +27,14 @@ const _Order = model
         mappedBy: undefined,
         foreignKey: true,
       })
+      .searchable()
       .nullable(),
     billing_address: model
       .hasOne<any>(() => OrderAddress, {
         mappedBy: undefined,
         foreignKey: true,
       })
+      .searchable()
       .nullable(),
     summary: model.hasMany<any>(() => OrderSummary, {
       mappedBy: "order",