Improve error handling for token auth

[luisjunco]

Issue

For token based auth, when a token is not valid or not provided, the api returns a 500 error.

Sending a 401 would be more appropriate plus, can help students to identify easier why their requests failed.

Solution

In error-handling\index.js, we can improve error handling adding the following:

//Unauthorized
if (err.name === "UnauthorizedError") {
  res.status(401).json({ message: `Unauthorized: ${err.inner?.message}` });
}