Check self references in metric agg after last doc collection (#33593)

(#34001)

* Check self references in metric agg after last doc collection (#33593)

* Revert 0aff5a3 (#33593)

* Check self refs in metric agg only once in post collection hook
(#33593)

* Remove unnecessary mocking (#33593)

Author: cbismuth

server/src/main/java/org/elasticsearch/search/aggregations/metrics/scripted/ScriptedMetricAggregator.java

@@ -75,7 +75,6 @@ public void collect(int doc, long bucket) throws IOException {
 
                 leafMapScript.setDocument(doc);
                 leafMapScript.execute();
-                CollectionUtils.ensureNoSelfReferences(aggState);
             }
         };
     }
@@ -98,4 +97,10 @@ public InternalAggregation buildEmptyAggregation() {
         return new InternalScriptedMetric(name, null, reduceScript, pipelineAggregators(), metaData());
     }
 
+    @Override
+    protected void doPostCollection() throws IOException {
+        CollectionUtils.ensureNoSelfReferences(aggState);
+
+        super.doPostCollection();
+    }
 }