### 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
DFS {
            @Override
            void addResultsObject(SearchContext context) {
                context.addDfsResult();
            }
        },
        QUERY {
            @Override
            void addResultsObject(SearchContext context) {
                context.addQueryResult();
            }
        },
        FETCH {
            @Override
            void addResultsObject(SearchContext context) {
                context.addFetchResult();
            }
        },
        /**
         * None is intended for use in testing, when we might not progress all the way to generating results
         */
        NONE {
            @Override
            void addResultsObject(SearchContext context) {
                
            }
        };
        abstract void addResultsObject(SearchContext context);
    }
    class Reaper implements Runnable {