ESQL: Reenable another heap attack (elastic#121572)

This one was disabled by a long-closed issue.

Author: nik9000

test/external-modules/esql-heap-attack/src/javaRestTest/java/org/elasticsearch/xpack/esql/heap_attack/HeapAttackIT.java

@@ -615,7 +615,6 @@ public void testFetchMvLongs() throws IOException {
         assertMap(map, matchesMap().entry("columns", columns));
     }
 
-    @AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/106683")
     public void testFetchTooManyMvLongs() throws IOException {
         initMvLongsIndex(500, 100, 1000);
         assertCircuitBreaks(() -> fetchMvLongs());