### 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
EmptyStoreRecoverySource.INSTANCE,
            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo")
        );
        test_0 = ShardRoutingHelper.initialize(test_0, node_0.getId());
        test_0 = ShardRoutingHelper.moveToStarted(test_0);
        shardRoutingMap.put(test_0, "/node0/least");
        ShardRouting test_1 = ShardRouting.newUnassigned(
            new ShardId(indexMetadata.getIndex(), 1),
            true,
            EmptyStoreRecoverySource.INSTANCE,
            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo")
        );
        test_1 = ShardRoutingHelper.initialize(test_1, node_1.getId());
        test_1 = ShardRoutingHelper.moveToStarted(test_1);
        shardRoutingMap.put(test_1, "/node1/least");
        ShardRouting test_2 = ShardRouting.newUnassigned(
            new ShardId(indexMetadata.getIndex(), 2),
            true,
            EmptyStoreRecoverySource.INSTANCE,
            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo")
        );
        test_2 = ShardRoutingHelper.initialize(test_2, node_1.getId());
        test_2 = ShardRoutingHelper.moveToStarted(test_2);
        shardRoutingMap.put(test_2, "/node1/most");
        ShardRouting test_3 = ShardRouting.newUnassigned(
            new ShardId(indexMetadata.getIndex(), 3),
            true,
            EmptyStoreRecoverySource.INSTANCE,
            new UnassignedInfo(UnassignedInfo.Reason.INDEX_CREATED, "foo")
        );