### Description

It should be enough to have ShardId + nodeId key in `routingToDataPath` to find the necessary data path. 
Changing the key would allow us to minimize the size of ClusterInfo size and find the data path when shard changes its status.

`ClusterInfo` might be sent over the wire when cluster allocation explain is executed with `includeDiskInfo=true`.
ShardRouting -> ShardId + nodeId conversion is trivial. The oposit would require additional information that could be faked.

Current key is also used in here:
https://github.com/elastic/elasticsearch/blob/9ebbe1c62bf0157d332f20f392544a1921a710df/server/src/main/java/org/elasticsearch/cluster/ClusterInfo.java#L149-L154
where it produces a string with ShardRouting#shortSummary that is excessive and might be simplified to ShardId + nodeId as well
server/src/test/java/org/elasticsearch/cluster/routing/allocation/decider/DiskThresholdDeciderUnitTests.java
Map<String, DiskUsage> leastAvailableUsages = Map.of("node_0", new DiskUsage("node_0", "node_0", "_na_", 100, 0)); 
        Map<String, DiskUsage> mostAvailableUsage = Map.of("node_0", new DiskUsage("node_0", "node_0", "_na_", 100, 0)); 
        Map<String, Long> shardSizes = new HashMap<>();
        
        final long shardSize = randomIntBetween(1, 10);
        shardSizes.put("[test][0][p]", shardSize);
        ClusterInfo clusterInfo = new ClusterInfo(leastAvailableUsages, mostAvailableUsage, shardSizes, Map.of(), Map.of(), Map.of());
        RoutingAllocation allocation = new RoutingAllocation(
            new AllocationDeciders(Collections.singleton(decider)),
            clusterState,
            clusterInfo,
            null,
            System.nanoTime()
        );
        allocation.debugDecision(true);
        Decision decision = decider.canForceAllocateDuringReplace(test_0, RoutingNodesHelper.routingNode("node_0", node_0), allocation);
        assertEquals(Decision.Type.NO, decision.type());
        assertThat(
            decision.getExplanation(),
            containsString(
                "unable to force allocate shard to [node_0] during replacement, "
                    + "as allocating to this node would cause disk usage to exceed 100% (["
                    + shardSize
                    + "] bytes above available disk space)"
            )
        );
    }
}