Push removal of search workers pool setting to v10 (elastic#118877)

The search workers thread pool has been removed in 8.16. We still support
parsing its size and queue size settings, to prevent issues upon upgrade
for users that may have customized them. We will provide such compatibility
for the entire 9.x series.

Author: javanna

server/src/main/java/org/elasticsearch/node/NodeConstruction.java

@@ -83,7 +83,7 @@
 import org.elasticsearch.core.SuppressForbidden;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.core.Tuple;
-import org.elasticsearch.core.UpdateForV9;
+import org.elasticsearch.core.UpdateForV10;
 import org.elasticsearch.discovery.DiscoveryModule;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.env.NodeEnvironment;
@@ -553,9 +553,10 @@ private SettingsModule validateSettings(Settings envSettings, Settings settings,
         return settingsModule;
     }
 
-    @UpdateForV9(owner = UpdateForV9.Owner.SEARCH_FOUNDATIONS)
+    @UpdateForV10(owner = UpdateForV10.Owner.SEARCH_FOUNDATIONS)
     private static void addBwcSearchWorkerSettings(List<Setting<?>> additionalSettings) {
-        // TODO remove the below settings, they are unused and only here to enable BwC for deployments that still use them
+        // Search workers thread pool has been removed in Elasticsearch 8.16.0. These settings are deprecated and take no effect.
+        // They are here only to enable BwC for deployments that still use them
         additionalSettings.add(
             Setting.intSetting("thread_pool.search_worker.queue_size", 0, Setting.Property.NodeScope, Setting.Property.DeprecatedWarning)
         );