### 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/test/java/org/elasticsearch/xpack/core/DataTiersUsageTransportActionTests.java
IndexMetadata warmIndex1 = indexMetadata("warm_index_1", 1, 1, DataTier.DATA_WARM);
        metadataBuilder.put(warmIndex1, false).generateClusterUuidIfNeeded();
        {
            IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(warmIndex1.getIndex());
            routeTestShardToNodes(warmIndex1, 0, indexRoutingTableBuilder, dataNode1, dataNode2);
            routingTableBuilder.add(indexRoutingTableBuilder.build());
        }
        IndexMetadata warmIndex2 = indexMetadata("warm_index_2", 1, 1, DataTier.DATA_WARM);
        metadataBuilder.put(warmIndex2, false).generateClusterUuidIfNeeded();
        {
            IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(warmIndex2.getIndex());
            routeTestShardToNodes(warmIndex2, 0, indexRoutingTableBuilder, dataNode3, dataNode1);
            routingTableBuilder.add(indexRoutingTableBuilder.build());
        }
        IndexMetadata coldIndex1 = indexMetadata("cold_index_1", 1, 0, DataTier.DATA_COLD);
        metadataBuilder.put(coldIndex1, false).generateClusterUuidIfNeeded();
        {
            IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(coldIndex1.getIndex());
            routeTestShardToNodes(coldIndex1, 0, indexRoutingTableBuilder, dataNode1);
            routingTableBuilder.add(indexRoutingTableBuilder.build());
        }
        IndexMetadata coldIndex2 = indexMetadata("cold_index_2", 1, 0, DataTier.DATA_COLD);
        metadataBuilder.put(coldIndex2, false).generateClusterUuidIfNeeded();
        {
            IndexRoutingTable.Builder indexRoutingTableBuilder = IndexRoutingTable.builder(coldIndex2.getIndex());
            routeTestShardToNodes(coldIndex2, 0, indexRoutingTableBuilder, dataNode2);
            routingTableBuilder.add(indexRoutingTableBuilder.build());
        }
        IndexMetadata coldIndex3 = indexMetadata("cold_index_3", 1, 0, DataTier.DATA_COLD);
        metadataBuilder.put(coldIndex3, false).generateClusterUuidIfNeeded();