http2: fix ping callback

In case there was no ack, the callback would have returned
more than the error as return value. This makes sure that is not
the case anymore.

PR-URL: #20311
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>

lib/internal/http2/core.js

@@ -704,8 +704,11 @@ const proxySocketHandler = {
 // data received on the PING acknowlegement.
 function pingCallback(cb) {
   return function pingCallback(ack, duration, payload) {
-    const err = ack ? null : new ERR_HTTP2_PING_CANCEL();
-    cb(err, duration, payload);
+    if (ack) {
+      cb(null, duration, payload);
+    } else {
+      cb(new ERR_HTTP2_PING_CANCEL());
+    }
   };
 }