Schema registry client shouldn't try to parse error response bodies

[joelezellLP]

I just spent days trying to debug a problem which initially looked like a JSON parsing issue but which turned out to be a HTTP gateway timeout. It sure would have been nice if the schema registry client had just logged the error code and message body. It looks like this behavior was corrected for auth errors, but it should have been addressed more broadly.
#733

I also see that there's a MR to do a broader fix, but it's been in existence since 2019 and I feel that the implementation should be different. Basically, if you get a 4xx or 5xx response, just log that error code and the raw message body.
#1200

There are a number of other posts on various forums about this sort of error so it's confusing a whole bunch of people out there. Here's the exception I got:

io.confluent.kafka.schemaregistry.client.rest.exceptions.RestClientException: Unrecognized token 'upstream': was expecting (JSON String, Number (or 'NaN'/'INF'/'+INF'), Array, Object or token 'null', 'true' or 'false')

[chile12]

@joelezellLP I would agree with you completely.
Yet, may I know how you resolved the issue itself, as I receive the same exception from the registry, trying to register a json schema.

[rayokota]

Fixed by #2642