Mark Core/Infra Rest API for serverless (elastic#95422)

This commit exposes core/infra owned REST APIs for serverless deployment.
It uses @ServerlessScope(Scope.PUBLIC) to achieve this.

follows up on elastic#94037

Author: pgomulka

modules/lang-painless/src/main/java/org/elasticsearch/painless/action/PainlessExecuteAction.java

@@ -60,6 +60,8 @@
 import org.elasticsearch.painless.spi.PainlessTestScript;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestToXContentListener;
 import org.elasticsearch.script.BooleanFieldScript;
 import org.elasticsearch.script.CompositeFieldScript;
@@ -721,6 +723,7 @@ private static Response prepareRamIndex(
         }
     }
 
+    @ServerlessScope(Scope.PUBLIC)
     public static class RestAction extends BaseRestHandler {
 
         @Override

server/src/main/java/org/elasticsearch/rest/action/RestMainAction.java

@@ -26,7 +26,7 @@
 import static org.elasticsearch.rest.RestRequest.Method.GET;
 import static org.elasticsearch.rest.RestRequest.Method.HEAD;
 
-@ServerlessScope(Scope.INTERNAL)
+@ServerlessScope(Scope.PUBLIC)
 public class RestMainAction extends BaseRestHandler {
 
     @Override

server/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestGetScriptContextAction.java

@@ -13,13 +13,16 @@
 import org.elasticsearch.client.internal.node.NodeClient;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
 import java.util.List;
 
 import static org.elasticsearch.rest.RestRequest.Method.GET;
 
+@ServerlessScope(Scope.PUBLIC)
 public class RestGetScriptContextAction extends BaseRestHandler {
 
     @Override

server/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestGetScriptLanguageAction.java

@@ -13,13 +13,16 @@
 import org.elasticsearch.client.internal.node.NodeClient;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestToXContentListener;
 
 import java.io.IOException;
 import java.util.List;
 
 import static org.elasticsearch.rest.RestRequest.Method.GET;
 
+@ServerlessScope(Scope.PUBLIC)
 public class RestGetScriptLanguageAction extends BaseRestHandler {
 
     @Override

server/src/main/java/org/elasticsearch/rest/action/admin/cluster/RestNodesHotThreadsAction.java

@@ -20,6 +20,8 @@
 import org.elasticsearch.rest.RestRequest;
 import org.elasticsearch.rest.RestResponse;
 import org.elasticsearch.rest.RestStatus;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestResponseListener;
 
 import java.io.IOException;
@@ -28,6 +30,7 @@
 
 import static org.elasticsearch.rest.RestRequest.Method.GET;
 
+@ServerlessScope(Scope.INTERNAL)
 public class RestNodesHotThreadsAction extends BaseRestHandler {
 
     private static final String formatDeprecatedMessageWithoutNodeID = "[%s] is a deprecated endpoint. "

server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestAnalyzeIndexDiskUsageAction.java

@@ -17,6 +17,8 @@
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.RestHandler;
 import org.elasticsearch.rest.RestRequest;
+import org.elasticsearch.rest.Scope;
+import org.elasticsearch.rest.ServerlessScope;
 import org.elasticsearch.rest.action.RestCancellableNodeClient;
 import org.elasticsearch.rest.action.RestToXContentListener;
 
@@ -25,6 +27,7 @@
 
 import static org.elasticsearch.rest.RestRequest.Method.POST;
 
+@ServerlessScope(Scope.PUBLIC)
 public class RestAnalyzeIndexDiskUsageAction extends BaseRestHandler {
 
     @Override