chore(medusa): rm default created at field (#8213)

**What**
To maintain the backward compatibility, we use to populate `created_at` no matter what. But since we can break things from v1, I ll remove it as we moved the default ordering to the repository layer

packages/medusa/src/api/utils/__tests__/validate-query.spec.ts

@@ -195,7 +195,7 @@ describe("validateAndTransformQuery", () => {
 
     expect(mockRequest.listConfig).toEqual(
       expect.objectContaining({
-        select: ["id", "created_at"],
+        select: ["id"],
       })
     )
 
@@ -406,13 +406,13 @@ describe("validateAndTransformQuery", () => {
 
     expect(mockRequest.listConfig).toEqual(
       expect.objectContaining({
-        select: ["store.name", "created_at", "id"],
+        select: ["store.name", "id"],
         relations: ["store"],
       })
     )
     expect(mockRequest.remoteQueryConfig).toEqual(
       expect.objectContaining({
-        fields: ["store.name", "created_at", "id"],
+        fields: ["store.name", "id"],
       })
     )
   })

packages/medusa/src/utils/get-query-config.ts

@@ -1,10 +1,11 @@
 import {
   getSetDifference,
+  isDefined,
   isPresent,
+  MedusaError,
   stringToSelectRelationObject,
 } from "@medusajs/utils"
 import { pick } from "lodash"
-import { MedusaError, isDefined } from "@medusajs/utils"
 import { RequestQueryFields } from "@medusajs/types"
 import { FindConfig, QueryConfig } from "../types/common"
 
@@ -76,10 +77,6 @@ export function prepareListQuery<T extends RequestQueryFields, TEntity>(
       })
     }
 
-    // TODO: Maintain backward compatibility, remove in future. the created at was only added in the list query for default order
-    if (queryConfig.isList) {
-      allFields.add("created_at")
-    }
     allFields.add("id")
   }