ES|QL: fix generative tests

Author: luigidellaquila

muted-tests.yml

@@ -441,9 +441,6 @@ tests:
 - class: org.elasticsearch.action.admin.cluster.state.TransportClusterStateActionDisruptionIT
   method: testLocalRequestWaitsForMetadata
   issue: https://github.com/elastic/elasticsearch/issues/127466
-- class: org.elasticsearch.xpack.esql.qa.single_node.GenerativeIT
-  method: test
-  issue: https://github.com/elastic/elasticsearch/issues/127536
 - class: org.elasticsearch.xpack.esql.qa.mixed.MixedClusterEsqlSpecIT
   method: test {union_types.MultiIndexSortIpStringEval ASYNC}
   issue: https://github.com/elastic/elasticsearch/issues/127537

x-pack/plugin/esql/qa/server/src/main/java/org/elasticsearch/xpack/esql/qa/rest/generative/EsqlQueryGenerator.java

@@ -226,6 +226,8 @@ private static String keep(List<Column> previousOutput) {
     private static String randomName(List<Column> previousOutput) {
         String result = randomRawName(previousOutput);
         if (result.isEmpty() // bug https://github.com/elastic/elasticsearch/issues/125870, we'll manage it as an error later
+            || result.contains("<")
+            || result.contains(">")
             || (randomBoolean() && result.contains("*") == false)) {
             result = "`" + result + "`";
         }