### 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
searchContextId = parser.text();
                } else if (TOOK.match(currentFieldName, parser.getDeprecationHandler())) {
                    tookInMillis = parser.longValue();
                } else if (TIMED_OUT.match(currentFieldName, parser.getDeprecationHandler())) {
                    timedOut = parser.booleanValue();
                } else if (TERMINATED_EARLY.match(currentFieldName, parser.getDeprecationHandler())) {
                    terminatedEarly = parser.booleanValue();
                } else if (NUM_REDUCE_PHASES.match(currentFieldName, parser.getDeprecationHandler())) {
                    numReducePhases = parser.intValue();
                } else {
                    parser.skipChildren();
                }
            } else if (token == Token.START_OBJECT) {
                if (SearchHits.Fields.HITS.equals(currentFieldName)) {
                    hits = SearchHits.fromXContent(parser);
                } else if (Aggregations.AGGREGATIONS_FIELD.equals(currentFieldName)) {
                    aggs = Aggregations.fromXContent(parser);
                } else if (Suggest.NAME.equals(currentFieldName)) {
                    suggest = Suggest.fromXContent(parser);
                } else if (SearchProfileResults.PROFILE_FIELD.equals(currentFieldName)) {
                    profile = SearchProfileResults.fromXContent(parser);
                } else if (RestActions._SHARDS_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
                    while ((token = parser.nextToken()) != Token.END_OBJECT) {
                        if (token == Token.FIELD_NAME) {
                            currentFieldName = parser.currentName();
                        } else if (token.isValue()) {
                            if (RestActions.FAILED_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
                                parser.intValue(); 
                            } else if (RestActions.SUCCESSFUL_FIELD.match(currentFieldName, parser.getDeprecationHandler())) {
                                successfulShards = parser.intValue();