fix(core-flows, medusa): Prevent cart addresses duplication on update (#13841)

* Allow id field in addresses properties for cart update validator

* Update cart addresses in update step where id is provided, both reference and nested fields

* Add tests

* Add changeset

* Remove unnecessary map step

* Review changes

packages/medusa/src/api/store/carts/validators.ts

@@ -43,13 +43,17 @@ export const StoreRemoveCartPromotions = z
   })
   .strict()
 
+const StoreCartUpsertAddress = AddressPayload.merge(z.object({
+	id: z.string().optional(),
+}))
+
 export type StoreUpdateCartType = z.infer<typeof UpdateCart>
 export const UpdateCart = z
   .object({
     region_id: z.string().optional(),
     email: z.string().email().nullish(),
-    billing_address: z.union([AddressPayload, z.string()]).optional(),
-    shipping_address: z.union([AddressPayload, z.string()]).optional(),
+    billing_address: z.union([StoreCartUpsertAddress, z.string()]).optional(),
+    shipping_address: z.union([StoreCartUpsertAddress, z.string()]).optional(),
     sales_channel_id: z.string().nullish(),
     metadata: z.record(z.unknown()).nullish(),
     promo_codes: z.array(z.string()).optional(),