_mvt endpoint does not include cross cluster prefix with `_index` value. For example, `_index` returns `myIndexPattern` instead of expected `cluster_one:myIndexPattern`. _search endpoint includes cross cluster prefix with `_index` value. This is causing problems in [Kibana maps tooltips](https://github.com/elastic/kibana/issues/153210)
x-pack/plugin/vector-tile/src/main/java/org/elasticsearch/xpack/vectortile/rest/RestVectorTileAction.java
final MvtLayerProps layerProps,
        String requestField,
        Map<String, DocumentField> fields
    ) {
        for (String field : fields.keySet()) {
            if ((requestField.equals(field) == false) && (field.equals(LABEL_POSITION_FIELD_NAME) == false)) {
                VectorTileUtils.addPropertyToFeature(featureBuilder, layerProps, field, fields.get(field).getValue());
            }
        }
    }
    private static VectorTile.Tile.Layer.Builder buildAggsLayer(
        InternalGeoGrid<?> grid,
        VectorTileRequest request,
        FeatureFactory featureFactory
    ) throws IOException {
        final VectorTile.Tile.Layer.Builder aggLayerBuilder = VectorTileUtils.createLayerBuilder(AGGS_LAYER, request.getExtent());
        final MvtLayerProps layerProps = new MvtLayerProps();
        final VectorTile.Tile.Feature.Builder featureBuilder = VectorTile.Tile.Feature.newBuilder();
        for (InternalGeoGridBucket bucket : grid.getBuckets()) {
            featureBuilder.clear();
            final String bucketKey = bucket.getKeyAsString();
            final byte[] feature = request.getGridType().toFeature(request.getGridAgg(), bucket, bucketKey, featureFactory);
            if (feature == null) {
                
                assert request.getGridAgg() == GridAggregation.GEOHEX;
                continue;
            }
            
            featureBuilder.mergeFrom(feature);