failed PayPal API request causing strange error (376)

[AlexP11223]

CRITICAL Uncaught TypeError: Argument 3 passed to WooCommerce\PayPalCommerce\ApiClient\Endpoint\OrderEndpoint::request_response_string() must be of the type array, object given

This error comes after the API answer and is causing the order processing to fail (or fatal errors in some places).

Is likely caused by this line which is supposed to log the answer in an array.

$this->logger->debug( $this->request_response_string( $url, $args, $response ) );

Most of the time it works, but sometimes when getting the API response we get an object instead of an array.

Steps to reproduce

1. Make PayPal API inaccessible, such as by disabling internet in local env or blocking api.paypal.com via hosts or firewall.
2. Make something to trigger a request to API, such as opening the webhooks status page or performing checkout.

Expected behaviour

The error should be logged properly, not causing fatal errors during logging.

Possible cause

Not handling failed requests which may return WP_Error instead of response.