### 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/main/java/org/elasticsearch/cluster/routing/allocation/decider/DiskThresholdDecider.java
allocation.routingTable()
        );
        assert shardSize >= 0 : shardSize;
        long freeBytesAfterShard = freeBytes - shardSize;
        if (freeBytesAfterShard < diskThresholdSettings.getFreeBytesThresholdHighStage(total).getBytes()) {
            logger.warn(
                "after allocating [{}] node [{}] would be above the high watermark setting [{}], having less than the minimum "
                    + "required {} of free space (actual free: {}, actual used: {}, estimated shard size: {}), preventing allocation",
                shardRouting,
                node.nodeId(),
                diskThresholdSettings.describeHighThreshold(total, false),
                diskThresholdSettings.getFreeBytesThresholdHighStage(total),
                freeBytesValue,
                Strings.format1Decimals(usedDiskPercentage, "%"),
                new ByteSizeValue(shardSize)
            );
            return allocation.decision(
                Decision.NO,
                NAME,
                "allocating the shard to this node will bring the node above the high watermark cluster setting [%s] "
                    + "and cause it to have less than the minimum required [%s] of free space (free: [%s], used: [%s], estimated "
                    + "shard size: [%s])",
                diskThresholdSettings.describeHighThreshold(total, true),
                diskThresholdSettings.getFreeBytesThresholdHighStage(total),
                freeBytesValue,
                Strings.format1Decimals(usedDiskPercentage, "%"),
                new ByteSizeValue(shardSize)
            );
        }
        assert freeBytesAfterShard >= 0 : freeBytesAfterShard;