### Elasticsearch Version

8.1.2

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

ESS on Azure

### Problem Description

The `_xpack/usage` API reports the size of the data set per data tier. However, it uses the local disk size as the metric it reports on and this is 0 (zero) for partially mounted indices, hiding the size of the data set mounted on the frozen tier.

We should switch to using the `total_data_set_size` metric that was introduced when we added the frozen tier/partially mounted indices.

### Steps to Reproduce

Mount a partially mounted index on a dedicated frozen tier. Use the `_xpack/usage` API and see that no (or very little) data is reported on frozen tier.

### Logs (if relevant)

_No response_
x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/DataTiersUsageTransportAction.java
aggregateDataTierShardStats(nodeStats, index, node, accumulator);
        }
    }
    /**
     * Collect shard-level data tier stats from shard stats contained in the node stats response.
     */
    private static void aggregateDataTierShardStats(NodeStats nodeStats, Index index, RoutingNode node, TierStatsAccumulator accumulator) {
        
        final List<IndexShardStats> allShardStats = nodeStats.getIndices().getShardStats(index);
        if (allShardStats != null) {
            for (IndexShardStats shardStat : allShardStats) {
                accumulator.totalByteCount += shardStat.getTotal().getStore().getSizeInBytes();
                accumulator.docCount += shardStat.getTotal().getDocs().getCount();
                
                if (node.getByShardId(shardStat.getShardId()).state() == ShardRoutingState.STARTED) {
                    accumulator.totalShardCount += 1;
                    
                    StoreStats primaryStoreStats = shardStat.getPrimary().getStore();
                    if (primaryStoreStats != null) {
                        
                        accumulator.primaryShardCount++;
                        long primarySize = primaryStoreStats.getSizeInBytes();
                        accumulator.primaryByteCount += primarySize;
                        accumulator.valueSketch.add(primarySize);
                    }
                }
            }
        }
    }
    private static DataTiersFeatureSetUsage.TierSpecificStats calculateFinalTierStats(TierStatsAccumulator accumulator) {