### Description

In [siren federate](https://siren.io/federate/) we extend the `SearchService` to create `SearchContext` instances. In 8.8 this is not possible anymore because the `createContext` method takes the `ResultsType` enum which is package private.

https://github.com/elastic/elasticsearch/blob/b640c217cccab67dce7d954bc92b6b519c102b16/server/src/main/java/org/elasticsearch/search/SearchService.java#L992-L998

In order to be able to keep on calling that method from another package, the visibility of the enum `ResultsType` should be increased to `protected`.
server/src/main/java/org/elasticsearch/search/SearchService.java
context.getSearchExecutionContext().freezeContext();
        if (canCache) {
            indicesService.loadIntoContext(request, context);
        } else {
            QueryPhase.execute(context);
        }
    }
    public void executeQueryPhase(ShardSearchRequest request, SearchShardTask task, ActionListener<SearchPhaseResult> listener) {
        assert request.canReturnNullResponseIfMatchNoDocs() == false || request.numberOfShards() > 1
            : "empty responses require more than one shard";
        final IndexShard shard = getShard(request);
        rewriteAndFetchShardRequest(shard, request, listener.delegateFailure((l, orig) -> {
            
            if (orig.canReturnNullResponseIfMatchNoDocs()) {
                assert orig.scroll() == null;
                final CanMatchShardResponse canMatchResp;
                try {
                    ShardSearchRequest clone = new ShardSearchRequest(orig);
                    canMatchResp = canMatch(clone, false);
                } catch (Exception exc) {
                    l.onFailure(exc);
                    return;
                }
                if (canMatchResp.canMatch() == false) {
                    l.onResponse(QuerySearchResult.nullInstance());
                    return;
                }
            }
            ensureAfterSeqNoRefreshed(shard, orig, () -> executeQueryPhase(orig, task), l);
        }));