_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
private static final String INDEX_TAG = "_index";
    private static final String KEY_TAG = "_key";
    
    private static final String MIME_TYPE = "application/vnd.mapbox-vector-tile";
    
    private static final String INTERNAL_AGG_PREFIX = "_mvt_";
    
    static final String CENTROID_AGG_NAME = INTERNAL_AGG_PREFIX + "centroid";
    
    static final String LABEL_POSITION_FIELD_NAME = INTERNAL_AGG_PREFIX + "label_position";
    public RestVectorTileAction() {}
    @Override
    public List<Route> routes() {
        return List.of(new Route(GET, "{index}/_mvt/{field}/{z}/{x}/{y}"), new Route(POST, "{index}/_mvt/{field}/{z}/{x}/{y}"));
    }
    @Override
    public String getName() {
        return "vector_tile_action";
    }
    @Override
    protected RestChannelConsumer prepareRequest(RestRequest restRequest, NodeClient client) throws IOException {
        
        final RestCancellableNodeClient cancellableNodeClient = new RestCancellableNodeClient(client, restRequest.getHttpChannel());
        final VectorTileRequest request = VectorTileRequest.parseRestRequest(restRequest);
        final SearchRequestBuilder searchRequestBuilder = searchRequestBuilder(cancellableNodeClient, request);
        return channel -> searchRequestBuilder.execute(new RestResponseListener<>(channel) {
            @Override
            public RestResponse buildResponse(SearchResponse searchResponse) throws Exception {
                try (BytesStream bytesOut = Streams.flushOnCloseStream(channel.bytesOutput())) {
                    final FeatureFactory featureFactory = new FeatureFactory(