### 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
doStop();
        keepAliveReaper.cancel();
    }
    public void executeDfsPhase(ShardSearchRequest request, SearchShardTask task, ActionListener<SearchPhaseResult> listener) {
        final IndexShard shard = getShard(request);
        rewriteAndFetchShardRequest(shard, request, listener.delegateFailure((l, rewritten) -> {
            
            ensureAfterSeqNoRefreshed(shard, request, () -> executeDfsPhase(request, task), l);
        }));
    }
    private DfsSearchResult executeDfsPhase(ShardSearchRequest request, SearchShardTask task) throws IOException {
        ReaderContext readerContext = createOrGetReaderContext(request);
        try (
            Releasable scope = tracer.withScope(task);
            Releasable ignored = readerContext.markAsUsed(getKeepAlive(request));
            SearchContext context = createContext(readerContext, request, task, ResultsType.DFS, false)
        ) {
            dfsPhase.execute(context);
            return context.dfsResult();
        } catch (Exception e) {
            logger.trace("Dfs phase failed", e);
            processFailure(readerContext, e);
            throw e;
        }
    }
    /**
     * Try to load the query results from the cache or execute the query phase directly if the cache cannot be used.
     */
    private void loadOrExecuteQueryPhase(final ShardSearchRequest request, final SearchContext context) throws Exception {
        final boolean canCache = IndicesService.canCache(request, context);