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

Author: elasticsearchmachine

muted-tests.yml

@@ -524,3 +524,6 @@ tests:
 - class: org.elasticsearch.xpack.ml.packageloader.action.ModelLoaderUtilsTests
   method: testSplitIntoRanges
   issue: https://github.com/elastic/elasticsearch/issues/121799
+- class: org.elasticsearch.xpack.esql.heap_attack.HeapAttackIT
+  method: testLookupExplosionBigStringManyMatches
+  issue: https://github.com/elastic/elasticsearch/issues/121465