fixing weight null check

Signed-off-by: Sandesh Kumar <sandeshkr419@gmail.com>

server/src/main/java/org/opensearch/search/aggregations/bucket/terms/GlobalOrdinalsStringTermsAggregator.java

@@ -170,21 +170,16 @@ LeafBucketCollector termDocFreqCollector(
         SortedSetDocValues globalOrds,
         BiConsumer<Long, Integer> ordCountConsumer
     ) throws IOException {
-        if (weight == null) {
-            // Calculate weight if not assigned previously
-            this.weight = context.searcher().createWeight(context.query(), ScoreMode.COMPLETE_NO_SCORES, 1f);
+        if (weight == null || weight.count(ctx) != ctx.reader().maxDoc()) {
+            // Weight not assigned or top-level query does not match all docs in the segment.
+            return null;
         }
 
         if (weight.count(ctx) == 0) {
-            // No documents matches top level query on this segment, we can skip it
+            // No documents matches top level query on this segment, we can skip the segment
             return LeafBucketCollector.NO_OP_COLLECTOR;
         }
 
-        if (weight.count(ctx) != ctx.reader().maxDoc()) {
-            // Top-level query does not match all docs in this segment.
-            return null;
-        }
-
         Terms segmentTerms = ctx.reader().terms(this.fieldName);
         if (segmentTerms == null) {
             // Field is not indexed.