Improve error reporting when API server authorization fails

[mlwilkerson]

Sometimes, there's this error on the JavaScript console, when using a Kit:

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The body of the HTTP response is:

{"data":{"me":null},"errors":[{"locations":[{"column":9,"line":3}],"message":"unauthorized","path":["me"]}]}

Because this issue is apparently specific to authorization, and that can be discovered from the JSON data in the HTTP response, it may be better to indicate the cause of the problem as authorization.