CORS error in specific admin routes

[kevinrobert3]

Bug report

Describe the bug

Admin routes like /customers, /products, /orders have a cors error

System information

Medusa version (including plugins): Node.js version: v20.11.1 Database: Postgres Operating system: MacOS Browser (if relevant): Chrome

Steps to reproduce the behavior

1. Create a sample frontend App running on any port
2. Make sure you have added the CORS allowed domains e.g localhost:3000/your port to your medusa config file
3. Do a fetch call using any of the mentioned api routes e.gadmin/products
4. You will get cors error in your browser
5. Repeat with non-affected routes like admin/auth/token, admin/users , admin/users/{id} and the api call will succeed

Expected behavior

A 200 response from server with all routes

Screenshots

https://github.com/medusajs/medusa/assets/12913275/f85d94cd-8c90-4109-9ec8-b28158c95f0b

Code snippets

The below code will work

await fetch(
            `${process.env.NEXT_PUBLIC_MEDUSA_URL}/admin/users/usr_01HSDSC3DNQ0KG6DQPCESWH0AJ`,
            {
              method: "POST",
              headers: {
                "Content-Type": "application/json",
                Authorization:
                  "Bearer eyJhbGciOiJIUzI1NiIsInR5",
              },

              body: JSON.stringify({
                first_name: "Medusa",
              }),
            }
          );

The below will have a cors error

await fetch(
            `${process.env.NEXT_PUBLIC_MEDUSA_URL}/admin/products`,
            {
              method: "POST",
              headers: {
                "Content-Type": "application/json",
                Authorization:
                  "Bearer eyJhbGciOiJIUzI1NiIsInR5",
              },

              body: JSON.stringify({
                title: "Medusa",
              }),
            }
          );

Additional context

Had a hunch that this could be an issue affecting the admin routes that we have extended entities and services for, like products, customers, orders but api routes that do not have extended entities and services like sales_channels and customer_groups also have the cors error .ie /admin/sales-channels like that.