Don't retry when MQTT response is unauthorized

[justmobilize]

Update connection code to break out of the retry look when getting either a Incorrect username/password or Unauthorized response.

Noticed in #211, although doesn't fix the original post

Tested on a UM FeatherS3

[justmobilize]

@brentru willing to take a look?

[dhalbert]

I defer to @brentru on this.

[justmobilize]

@dhalbert So this shouldn't really solve anything other then getting a better error, and making it easier to debug. Unless the error they get is really retriable (which I asked above)