https://github.com/elastic/elasticsearch/pull/97304 removes several places that might do an expensive rebuild of the cluster state via `getStateForMasterService`. There's one other call we should be able to remove, in `JoinValidationService`, but it's a little tricky since we rely on seeing the last-accepted state for the cluster UUID validation, and it's not obviously ok to expose the last-accepted state without the no-master block.

This is a fairly minor issue because we do not do this join validation during elections, only if we're the elected master, and in that case `getStateForMasterService` is cheap. But that's not guaranteed, and we should strengthen this to avoid the that expensive step whenever possible.
server/src/main/java/org/elasticsearch/cluster/coordination/Coordinator.java
CoordinatorPeerFinder(
            Settings settings,
            TransportService transportService,
            TransportAddressConnector transportAddressConnector,
            ConfiguredHostsResolver configuredHostsResolver
        ) {
            super(
                settings,
                transportService,
                transportAddressConnector,
                singleNodeDiscovery ? hostsResolver -> {} : configuredHostsResolver
            );
        }
        @Override
        protected void onActiveMasterFound(DiscoveryNode masterNode, long term) {
            synchronized (mutex) {
                ensureTermAtLeast(masterNode, term);
                joinHelper.sendJoinRequest(masterNode, getCurrentTerm(), joinWithDestination(lastJoin, masterNode, term));