### 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
} else {
            return request.readerId() == null ? defaultKeepAlive : -1;
        }
    }
    private long getScrollKeepAlive(Scroll scroll) {
        if (scroll != null && scroll.keepAlive() != null) {
            checkKeepAliveLimit(scroll.keepAlive().millis());
            return scroll.keepAlive().getMillis();
        }
        return defaultKeepAlive;
    }
    private void checkKeepAliveLimit(long keepAlive) {
        if (keepAlive > maxKeepAlive) {
            throw new IllegalArgumentException(
                "Keep alive for request ("
                    + TimeValue.timeValueMillis(keepAlive)
                    + ") is too large. "
                    + "It must be less than ("
                    + TimeValue.timeValueMillis(maxKeepAlive)
                    + "). "
                    + "This limit can be set by changing the ["
                    + MAX_KEEPALIVE_SETTING.getKey()
                    + "] cluster level setting."
            );
        }
    }
    private <T> ActionListener<T> wrapFailureListener(ActionListener<T> listener, ReaderContext context, Releasable releasable) {
        return new ActionListener<>() {
            @Override
            public void onResponse(T resp) {