Fix ListObjectsV2 for gateway encryption mode (#7491)

Fixes #7468 by setting NextContinuationToken only if list is
truncated

cmd/gateway/s3/gateway-s3-sse.go

@@ -138,16 +138,19 @@ func (l *s3EncObjects) ListObjectsV2(ctx context.Context, bucket, prefix, contin
 	loi.ContinuationToken = continuationToken
 	loi.Objects = make([]minio.ObjectInfo, 0)
 	loi.Prefixes = make([]string, 0)
+	loi.Objects = append(loi.Objects, objects...)
 
-	for _, obj := range objects {
-		loi.NextContinuationToken = obj.Name
-		loi.Objects = append(loi.Objects, obj)
-	}
 	for _, pfx := range prefixes {
 		if pfx != prefix {
 			loi.Prefixes = append(loi.Prefixes, pfx)
 		}
 	}
+	// Set continuation token if s3 returned truncated list
+	if isTruncated {
+		if len(objects) > 0 {
+			loi.NextContinuationToken = objects[len(objects)-1].Name
+		}
+	}
 	return loi, nil
 }