RedirectSingle: avoid extra operator for exception handling path (#…

…3114)

Use new `Single.subscribe(...)` overload introduced in
[#3112](#3112) that takes
`errorConsumer` to avoid using extra operator `whenOnError`. It will
also help to avoid logging those exceptions by `SimpleSingleSubscriber`
(hard to relate to a real request) and instead they will only bubble up
on the caller path.

servicetalk-http-utils/src/main/java/io/servicetalk/http/utils/RedirectSingle.java

@@ -194,8 +194,8 @@ public void onSuccess(@Nullable final StreamingHttpResponse response) {
                 if (!terminalDelivered) {
                     // Drain response payload body before propagating the cause
                     sequentialCancellable.nextCancellable(response.messageBody().ignoreElements()
-                            .whenOnError(suppressed -> safeOnError(target, addSuppressed(cause, suppressed)))
-                            .subscribe(() -> safeOnError(target, cause)));
+                            .subscribe(() -> safeOnError(target, cause),
+                                    suppressed -> safeOnError(target, addSuppressed(cause, suppressed))));
                 } else {
                     LOGGER.info("Ignoring exception from onSuccess of Subscriber {}.", target, cause);
                 }