Remove @UpdateForV9 annotation in RuntimeVersionFeature

Re ES-10338 the Core/Infra team agreed that this is not blocked on security manager removal. We should go ahead and remove these 2 instances of the @UpdateForV9 annotation, the code will be cleaned up soon with the removal of Security Manager.

Author: arpadkiraly

libs/core/src/main/java/org/elasticsearch/jdk/RuntimeVersionFeature.java

@@ -9,12 +9,9 @@
 
 package org.elasticsearch.jdk;
 
-import org.elasticsearch.core.UpdateForV9;
-
 public class RuntimeVersionFeature {
     private RuntimeVersionFeature() {}
 
-    @UpdateForV9(owner = UpdateForV9.Owner.CORE_INFRA) // Remove once we removed all references to SecurityManager in code
     public static boolean isSecurityManagerAvailable() {
         return Runtime.version().feature() < 24;
     }