WORKOS_COOKIE_PASSWORD doc inconsistency

The current [README.md's WORKOS_COOKIE_PASSWORD instructions](https://github.com/workos/authkit-nextjs/blob/5df55e19004fe4a2c4c8023ceb339b806a810efd/README.md#pre-flight) recommend `openssl rand -base64 24` for password generation but the [WorkOS AuthKit instructions](https://workos.com/docs/authkit/nextjs#set-secrets) recommend `openssl rand -base64 32` The latter makes a ~45 character password with 32 bytes of entropy while the former makes a ~32 character password with 24 bytes of entropy. I guess it's a question of whether the length recommendation was asking for that many characters of entropy or for the total base64-encoded length.