Fix request timeout in HeapAttack tests (elastic#104336)

I noticed we're using 5 minutes for both query timeout and triggering 
the out-of-memory action in heap attack tests. This means when we're
generating the heap dump, and some ESQL tasks might get canceled because
the connection was disconnected. This PR increases the query timeout to
6 minutes instead.

test/external-modules/esql-heap-attack/src/javaRestTest/java/org/elasticsearch/xpack/esql/heap_attack/HeapAttackIT.java

@@ -310,7 +310,7 @@ private Response query(String query, String filterPath) throws IOException {
         request.setJsonEntity(query.toString().replace("\n", "\\n"));
         request.setOptions(
             RequestOptions.DEFAULT.toBuilder()
-                .setRequestConfig(RequestConfig.custom().setSocketTimeout(Math.toIntExact(TimeValue.timeValueMinutes(5).millis())).build())
+                .setRequestConfig(RequestConfig.custom().setSocketTimeout(Math.toIntExact(TimeValue.timeValueMinutes(6).millis())).build())
                 .setWarningsHandler(WarningsHandler.PERMISSIVE)
         );
         logger.info("--> test {} started querying", getTestName());
@@ -330,6 +330,10 @@ protected void doRun() throws Exception {
                     TimeValue elapsed = TimeValue.timeValueNanos(System.nanoTime() - startedTimeInNanos);
                     logger.info("--> test {} triggering OOM after {}", getTestName(), elapsed);
                     Request triggerOOM = new Request("POST", "/_trigger_out_of_memory");
+                    RequestConfig requestConfig = RequestConfig.custom()
+                        .setSocketTimeout(Math.toIntExact(TimeValue.timeValueMinutes(2).millis()))
+                        .build();
+                    request.setOptions(RequestOptions.DEFAULT.toBuilder().setRequestConfig(requestConfig));
                     client().performRequest(triggerOOM);
                 }
             }, TimeValue.timeValueMinutes(5), testThreadPool.executor(ThreadPool.Names.GENERIC));