Map timeout exceptions in payment gateway client into 502

[giovanniberti]

Here:

pagopa-ecommerce-transactions-service/src/main/java/it/pagopa/transactions/client/PaymentGatewayClient.java

Lines 63 to 67 in f6caa9c

	.onErrorMap(WebClientResponseException.class, exception -> switch (exception.getStatusCode()) {
	case UNAUTHORIZED -> new AlreadyProcessedException(authorizationData.transaction().getRptId());
	case GATEWAY_TIMEOUT -> new GatewayTimeoutException();
	case INTERNAL_SERVER_ERROR -> new BadGatewayException("");
	default -> exception;

(and others) the switch case falls through in case there's a timeout (=> no status code). We should bubble up a 502 HTTP status code/exception instead.