Fix minus

Author: leaves12138

paimon-format/src/main/java/org/apache/paimon/format/orc/writer/FieldWriterFactory.java

@@ -250,11 +250,6 @@ public FieldWriter visit(BlobType blobType) {
         return (rowId, column, getters, columnId) -> {
             BytesColumnVector vector = (BytesColumnVector) column;
             Blob blob = getters.getBlob(columnId);
-            if (blob == null) {
-                vector.isNull[rowId] = true;
-                vector.noNulls = false;
-                return 0;
-            }
             try {
                 BlobDescriptor descriptor = blob.toDescriptor();
                 byte[] bytes = descriptor.serialize();