Mute org.elasticsearch.xpack.esql.heap_attack.HeapAttackIT testLookupExplosionBigStringManyMatches elastic#121465

Author: elasticsearchmachine

muted-tests.yml

@@ -554,3 +554,6 @@ tests:
   issue: https://github.com/elastic/elasticsearch/issues/121179
 - class: org.elasticsearch.xpack.application.CohereServiceUpgradeIT
   issue: https://github.com/elastic/elasticsearch/issues/121537
+- class: org.elasticsearch.xpack.esql.heap_attack.HeapAttackIT
+  method: testLookupExplosionBigStringManyMatches
+  issue: https://github.com/elastic/elasticsearch/issues/121465