### 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/ClusterInfo.java
/**
     * Represents the total amount of "reserved" space on a particular data path, together with the set of shards considered.
     */
    public record ReservedSpace(long total, Set<ShardId> shardIds) implements Writeable {
        public static final ReservedSpace EMPTY = new ReservedSpace(0, new HashSet<>());
        ReservedSpace(StreamInput in) throws IOException {
            this(in.readVLong(), in.readSet(ShardId::new));
        }
        @Override
        public void writeTo(StreamOutput out) throws IOException {
            out.writeVLong(total);
            out.writeCollection(shardIds);
        }
        public long getTotal() {
            return total;
        }
        public boolean containsShardId(ShardId shardId) {
            return shardIds.contains(shardId);
        }
        void toXContent(XContentBuilder builder, Params params) throws IOException {
            builder.field("total", total);
            builder.startArray("shards");
            {
                for (ShardId shardIdCursor : shardIds) {
                    shardIdCursor.toXContent(builder, params);
                }
            }
            builder.endArray(); 
        }
        public static class Builder {