_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 META_LAYER = "meta";
    private static final String HITS_LAYER = "hits";
    private static final String AGGS_LAYER = "aggs";
    private static final String GRID_FIELD = "grid";
    private static final String BOUNDS_FIELD = "bounds";
    private static final String COUNT_TAG = "_count";
    private static final String ID_TAG = "_id";