Fix visit method of constant score query and function score query to iterate recursively

Signed-off-by: Varun Jain <varunudr@amazon.com>

Author: vibrantvarun

server/src/main/java/org/opensearch/index/query/ConstantScoreQueryBuilder.java

@@ -204,7 +204,9 @@ protected void extractInnerHitBuilders(Map<String, InnerHitContextBuilder> inner
     @Override
     public void visit(QueryBuilderVisitor visitor) {
         visitor.accept(this);
-        visitor.getChildVisitor(BooleanClause.Occur.FILTER).accept(filterBuilder);
+        if (filterBuilder != null) {
+            filterBuilder.visit(visitor.getChildVisitor(BooleanClause.Occur.FILTER));
+        }
     }
 
 }

server/src/main/java/org/opensearch/index/query/functionscore/FunctionScoreQueryBuilder.java

@@ -711,7 +711,7 @@ private static String parseFiltersAndFunctions(
     public void visit(QueryBuilderVisitor visitor) {
         visitor.accept(this);
         if (query != null) {
-            visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(query);
+            query.visit(visitor.getChildVisitor(BooleanClause.Occur.MUST));
         }
     }
 }