non-json errors from REST api cause Fatal Errors

[drekinov]

Hi,

related to recent servers error and one currently going on https://status.nordigen.com/incidents/w000r4t5mry6.

src/Http/RequestHandlerTrait.php handle BadResponseException which can be Client or Server side error.
In src/Http/RequestHandlerTrait.php#L41 api response is always processed as JSON and passed to getExceptionType which expects array.

 $json = json_decode($content, true);
 $errorType = self::getExceptionType($json);

private static function getExceptionType(array $response)

in case of 502 from load balancer or any other layer not handled by backend django rest framework . it can be NULL because Accept headers are not handled properly. that lead to php errors in sdk and Nordigen API errors are hidden and applications cannot properly handle outages.

Our Sentry is full of php errors instead of nordigen api errors that service return.