feat: Expose HTTP errors for non-JSON format response

[yinggeh]

What does the PR do?

When using the tritonclient.http or tritonclient.http.aio package to call a Triton server behind a gateway, and the gateway returns a non-200 status code with a message, the message might not be correctly raised to callers because it's not in JSON format.

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• feat

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• closes GitHub issue: HTTP Errors are not Correctly Exposed by the Python Client SDK #865