### Description

`SearchResponse.Clusters` currently uses a `HashMap<String, AtomicReference>` for storing Cluster objects. The AtomicReference CAS swaps are done in a do/while loop in most cases (e.g., in `CCSSingleCoordinatorSearchProgressListener`).

This can be replaced with a `ConcurrentHashMap` in conjunction with either `compute()` method or the `replace(key, assumed_previous_value, value)` method for atomically swapping in a new Cluster object with a CAS operation, assuring that the updates don't lose data from competing threads doing separate Cluster object updates.

See: https://github.com/elastic/elasticsearch/pull/98457/files#r1310467586 
server/src/main/java/org/elasticsearch/action/search/SearchResponse.java
/**
     * The number of shards skipped due to pre-filtering
     */
    public int getSkippedShards() {
        return skippedShards;
    }
    /**
     * The failed number of shards the search was executed on.
     */
    public int getFailedShards() {
        return shardFailures.length;
    }
    /**
     * The failures that occurred during the search.
     */
    public ShardSearchFailure[] getShardFailures() {
        return this.shardFailures;
    }
    /**
     * If scrolling was enabled ({@link SearchRequest#scroll(org.elasticsearch.search.Scroll)}, the
     * scroll id that can be used to continue scrolling.
     */
    public String getScrollId() {
        return scrollId;
    }
    /**
     * Returns the encoded string of the search context that the search request is used to executed
     */
    public String pointInTimeId() {
        return pointInTimeId;