### 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
/*
                 * The query on the search context right now doesn't include
                 * the filter for nested documents or slicing so we have to
                 * delay reading it until the aggs ask for it.
                 */
                () -> context.rewrittenQuery() == null ? new MatchAllDocsQuery() : context.rewrittenQuery(),
                context.getProfilers() == null ? null : context.getProfilers().getAggregationProfiler(),
                multiBucketConsumerService.getLimit(),
                () -> new SubSearchContext(context).parsedQuery(context.parsedQuery()).fetchFieldsContext(context.fetchFieldsContext()),
                context.bitsetFilterCache(),
                context.indexShard().shardId().hashCode(),
                context::getRelativeTimeInMillis,
                context::isCancelled,
                context::buildFilteredQuery,
                enableRewriteAggsToFilterByFilter,
                source.aggregations().isInSortOrderExecutionRequired()
            );
            context.addQuerySearchResultReleasable(aggContext);
            try {
                AggregatorFactories factories = source.aggregations().build(aggContext, null);
                context.aggregations(new SearchContextAggregations(factories));
            } catch (IOException e) {
                throw new AggregationInitializationException("Failed to create aggregators", e);
            }
        }
        if (source.suggest() != null) {
            try {
                context.suggest(source.suggest().build(searchExecutionContext));
            } catch (IOException e) {
                throw new SearchException(shardTarget, "failed to create SuggestionSearchContext", e);