### 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
Property.Dynamic
    );
    public static final Setting<Boolean> CCS_VERSION_CHECK_SETTING = Setting.boolSetting(
        "search.check_ccs_compatibility",
        false,
        Property.NodeScope
    );
    /**
     * Enables low-level, frequent search cancellation checks. Enabling low-level checks will make long running searches to react
     * to the cancellation request faster. It will produce more cancellation checks but benchmarking has shown these did not
     * noticeably slow down searches.
     */
    public static final Setting<Boolean> LOW_LEVEL_CANCELLATION_SETTING = Setting.boolSetting(
        "search.low_level_cancellation",
        true,
        Property.Dynamic,
        Property.NodeScope
    );
    public static final TimeValue NO_TIMEOUT = timeValueMillis(-1);
    public static final Setting<TimeValue> DEFAULT_SEARCH_TIMEOUT_SETTING = Setting.timeSetting(
        "search.default_search_timeout",
        NO_TIMEOUT,
        Property.Dynamic,
        Property.NodeScope
    );
    public static final Setting<Boolean> DEFAULT_ALLOW_PARTIAL_SEARCH_RESULTS = Setting.boolSetting(
        "search.default_allow_partial_results",
        true,
        Property.Dynamic,
        Property.NodeScope