APIv4 sudo no longer works

Summary

When attempting to use sudo the following error message is produced:

{"message":"403 Forbidden  - Private token must be specified in order to use sudo"}

Steps to reproduce

curl --header "PRIVATE-TOKEN: [redacted]" --header "SUDO: 1" https://gitlab.example.com/api/v4/user
curl --header "PRIVATE-TOKEN: [redacted]" https://gitlab.example.com/api/v4/user?sudo=1
curl "https://gitlab.example.com/api/v4/user?sudo=1&private_token=[redacted]"