### Description

We now support storing KNN vectors as part of our indexed data.  These vectors should be included in the disk usage API.
server/src/test/java/org/elasticsearch/action/admin/indices/diskusage/IndexDiskUsageAnalyzerTests.java
}
                    @Override
                    public DocValuesFormat getDocValuesFormatForField(String field) {
                        return new Lucene90DocValuesFormat();
                    }
                    @Override
                    public String toString() {
                        return super.toString();
                    }
                })
                .setOpenMode(IndexWriterConfig.OpenMode.CREATE);
            try (IndexWriter writer = new IndexWriter(dst, config)) {
                for (LeafReaderContext leaf : reader.leaves()) {
                    final SegmentReader segmentReader = Lucene.segmentReader(leaf.reader());
                    writer.addIndexes(segmentReader);
                }
                writer.commit();
            }
        }
    }
    static IndexDiskUsageStats collectPerFieldStats(Directory directory) throws IOException {
        try (DirectoryReader reader = DirectoryReader.open(directory)) {
            final IndexDiskUsageStats stats = new IndexDiskUsageStats(IndexDiskUsageAnalyzer.getIndexSize(lastCommit(directory)));
            for (LeafReaderContext leaf : reader.leaves()) {
                collectPerFieldStats(Lucene.segmentReader(leaf.reader()), stats);
            }
            return stats;
        }
    }
    static void collectPerFieldStats(SegmentReader reader, IndexDiskUsageStats stats) throws IOException {