fix: change visibility of SearchService#ResultsType to protected (#95671)

The `SearchService#createContext` method takes the recently added `ResultsType` enum which is package private. In order to be able to keep on calling that method, which is protected, from another package, the visibility of the enum `ResultsType` should be increased to protected. Closes #95670 Co-authored-by: Stéphane Campinas <stephane.campinas@gmail.com>

Author: javanna

server/src/main/java/org/elasticsearch/search/SearchService.java

@@ -1469,7 +1469,7 @@ public ResponseCollectorService getResponseCollectorService() {
  /**
  * Used to indicate which result object should be instantiated when creating a search context
  */
- enum ResultsType {
+ protected enum ResultsType {
  DFS {
  @Override
  void addResultsObject(SearchContext context) {