In #86101 we added a warning if bootstrapping was incorrectly configured (and in #92744 we changed it to be emitted every 12h). The logic introduced doesn't take account of `discovery.type: single-node`, so explicitly-single-node clusters will always emit this warning even though they are correctly configured.

Relates https://github.com/elastic/elasticsearch/issues/58393.
server/src/test/java/org/elasticsearch/cluster/coordination/ClusterBootstrapServiceTests.java
public void testCancelsBootstrapIfNodeMatchesMultipleRequirements() {
        AtomicReference<Iterable<DiscoveryNode>> discoveredNodes = new AtomicReference<>(List.of(otherNode1, otherNode2));
        ClusterBootstrapService clusterBootstrapService = new ClusterBootstrapService(
            Settings.builder()
                .putList(INITIAL_MASTER_NODES_SETTING.getKey(), otherNode1.getAddress().toString(), otherNode1.getName())
                .build(),
            transportService,
            discoveredNodes::get,
            () -> false,
            vc -> {
                throw new AssertionError("should not be called");
            }
        );
        transportService.start();
        clusterBootstrapService.onFoundPeersUpdated();
        deterministicTaskQueue.runAllTasks();
        discoveredNodes.set(
            List.of(
                DiscoveryNodeUtils.builder(randomAlphaOfLength(10))
                    .name(otherNode1.getName())
                    .roles(Set.of(DiscoveryNodeRole.MASTER_ROLE))
                    .build(),
                DiscoveryNodeUtils.builder(randomAlphaOfLength(10))
                    .name("yet-another-node")
                    .address(otherNode1.getAddress())
                    .roles(Set.of(DiscoveryNodeRole.MASTER_ROLE))
                    .build()
            )
        );
        clusterBootstrapService.onFoundPeersUpdated();