fix(medusa): cart now returns 404 when not found (#13622)

FIXES #10218 
FIXES CORE-739

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

@@ -1,6 +1,7 @@
 import { MedusaContainer } from "@medusajs/framework/types"
 import {
   ContainerRegistrationKeys,
+  MedusaError,
   remoteQueryObjectFromString,
 } from "@medusajs/framework/utils"
 
@@ -18,5 +19,12 @@ export const refetchCart = async (
 
   const [cart] = await remoteQuery(queryObject)
 
+  if (!cart) {
+    throw new MedusaError(
+      MedusaError.Types.NOT_FOUND,
+      `Cart with id '${id}' not found`
+    )
+  }
+
   return cart
 }