[Tests] Nudge wait time in RemoteClusterServiceTests (#33853)

This test occasionally fails in `testCollectSearchShards` waiting on what seems
to be a search request to a remote cluster for one second. Given that the test
fails here very rarely I suspect maybe one second is very rarely not enough so
we could fix it by increasing the max wait time slightly.

Closes #33852

Author: Christoph Büscher

server/src/test/java/org/elasticsearch/transport/RemoteClusterServiceTests.java

@@ -566,7 +566,7 @@ public void testCollectSearchShards() throws Exception {
                         remoteClusterService.collectSearchShards(IndicesOptions.lenientExpandOpen(), "index_not_found",
                                 null, remoteIndicesByCluster,
                                 new LatchedActionListener<>(ActionListener.wrap(response::set, failure::set), latch));
-                        assertTrue(latch.await(1, TimeUnit.SECONDS));
+                        assertTrue(latch.await(2, TimeUnit.SECONDS));
                         assertNull(response.get());
                         assertNotNull(failure.get());
                         assertThat(failure.get(), instanceOf(RemoteTransportException.class));