ESQL: Fix writing for LOOKUP status (#119296)

This fixes writing the `status` of the LOOKUP operator. It just wasn't
registered.

Closes #119086

Author: nik9000

docs/changelog/119296.yaml

@@ -0,0 +1,6 @@
+pr: 119296
+summary: Fix writing for LOOKUP status
+area: ES|QL
+type: bug
+issues:
+ - 119086

muted-tests.yml

@@ -230,8 +230,6 @@ tests:
   issue: https://github.com/elastic/elasticsearch/issues/115727
 - class: org.elasticsearch.xpack.security.authc.kerberos.KerberosAuthenticationIT
   issue: https://github.com/elastic/elasticsearch/issues/118414
-- class: org.elasticsearch.xpack.esql.qa.multi_node.EsqlClientYamlIT
-  issue: https://github.com/elastic/elasticsearch/issues/119086
 - class: org.elasticsearch.smoketest.DocsClientYamlTestSuiteIT
   method: test {yaml=reference/search/search-your-data/retrievers-examples/line_98}
   issue: https://github.com/elastic/elasticsearch/issues/119155

x-pack/plugin/esql/src/main/java/org/elasticsearch/xpack/esql/plugin/EsqlPlugin.java

@@ -61,6 +61,7 @@
 import org.elasticsearch.xpack.esql.action.RestEsqlGetAsyncResultAction;
 import org.elasticsearch.xpack.esql.action.RestEsqlQueryAction;
 import org.elasticsearch.xpack.esql.enrich.EnrichLookupOperator;
+import org.elasticsearch.xpack.esql.enrich.LookupFromIndexOperator;
 import org.elasticsearch.xpack.esql.execution.PlanExecutor;
 import org.elasticsearch.xpack.esql.expression.ExpressionWritables;
 import org.elasticsearch.xpack.esql.plan.PlanWritables;
@@ -192,6 +193,7 @@ public List<NamedWriteableRegistry.Entry> getNamedWriteables() {
         entries.add(SingleValueQuery.ENTRY);
         entries.add(AsyncOperator.Status.ENTRY);
         entries.add(EnrichLookupOperator.Status.ENTRY);
+        entries.add(LookupFromIndexOperator.Status.ENTRY);
 
         entries.addAll(BlockWritables.getNamedWriteables());
         entries.addAll(ExpressionWritables.getNamedWriteables());