Handle scenarios where response body contains unparseable JSON

[mkanoor]

If the response body contains an invalid JSON we should not raise an exception. Usually happens if the server ran into some error and couldn't send back a valid response body. These are typically the 5xx errors, server side errors.

e.g this is live data that came back from the RBAC service

{"@timestamp":"2020-05-07T08:52:38.780751 ","hostname":"catalog-api-89-46qw4","pid":27,"tid":"2ad1404721ec","level":"err","message":"RBACApiClient::ApiError: Error message: the server returns an error\nHTTP status code: 500\nResponse headers: {\"Server\"=\u003e\"gunicorn/19.9.0\", \"Date\"      =\u003e\"Thu, 07 May 2020 08:52:38 GMT\", \"Connection\"=\u003e\"keep-alive\", \"Content-Type\"=\u003e\"text/html\", \"Content-Length\"=\u003e\"2      7\", \"Vary\"=\u003e\"Origin\"}\nResponse body: \u003ch1\u003eServer Error (500)\u003c/h1\u003e ","request_id":"e2a456005ece40209f01ef5abb5a40de"

{"@timestamp":"2020-05-07T08:52:38.803570 ","hostname":"catalog-api-89-46qw4","pid":27,"tid":"2ad1404721ec","level":"crit","message":"JSON::ParserError (783: unexpected token at '\u003ch1\u003eServer Error (500)\u003c/h1\u003e'):"}