_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
.field(request.getField())
                .precision(request.getGridAgg().gridPrecisionToAggPrecision(request.getZ(), request.getGridPrecision()))
                .setGeoBoundingBox(boundingBox)
                .size(MultiBucketConsumerService.DEFAULT_MAX_BUCKETS);
            searchRequestBuilder.addAggregation(tileAggBuilder);
            searchRequestBuilder.addAggregation(new StatsBucketPipelineAggregationBuilder(COUNT_TAG, GRID_FIELD + "." + COUNT_TAG));
            if (request.getGridType() == GridType.CENTROID) {
                tileAggBuilder.subAggregation(new GeoCentroidAggregationBuilder(CENTROID_AGG_NAME).field(request.getField()));
            }
            final List<MetricsAggregationBuilder<?>> aggregations = request.getAggBuilder();
            for (MetricsAggregationBuilder<?> aggregation : aggregations) {
                if (aggregation.getName().startsWith(INTERNAL_AGG_PREFIX)) {
                    throw new IllegalArgumentException(
                        "Invalid aggregation name ["
                            + aggregation.getName()
                            + "]. Aggregation names cannot start with prefix '"
                            + INTERNAL_AGG_PREFIX
                            + "'"
                    );
                }
                tileAggBuilder.subAggregation(aggregation);
                final Set<String> metricNames = aggregation.metricNames();
                for (String metric : metricNames) {
                    final String bucketPath;
                    
                    if (metric.contains(".")) {
                        bucketPath = GRID_FIELD + ">" + aggregation.getName() + "[" + metric + "]";
                    } else {
                        bucketPath = GRID_FIELD + ">" + aggregation.getName() + "." + metric;
                    }