### 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
private static final Logger logger = LogManager.getLogger(SearchService.class);
    
    public static final Setting<TimeValue> DEFAULT_KEEPALIVE_SETTING = Setting.positiveTimeSetting(
        "search.default_keep_alive",
        timeValueMinutes(5),
        Property.NodeScope,
        Property.Dynamic
    );
    public static final Setting<TimeValue> MAX_KEEPALIVE_SETTING = Setting.positiveTimeSetting(
        "search.max_keep_alive",
        timeValueHours(24),
        Property.NodeScope,
        Property.Dynamic
    );
    public static final Setting<TimeValue> KEEPALIVE_INTERVAL_SETTING = Setting.positiveTimeSetting(
        "search.keep_alive_interval",
        timeValueMinutes(1),
        Property.NodeScope
    );
    public static final Setting<Boolean> ALLOW_EXPENSIVE_QUERIES = Setting.boolSetting(
        "search.allow_expensive_queries",
        true,
        Property.NodeScope,