Paypal - Overriding Payflowpro.php file is not working

Question

There is an official bug in Magento 2.2.3 of Paypal Payflow Pro, It is sending comment_1 parameter to Paypal instead of comment1, And Paypal is ignoring this parameter

Magento Team acknowledge this issue: (https://github.com/magento/magento2/issues/15163 )

Now to fix it, I am trying to override \Magento\Paypal\Model\Payflowpro model file

But it's not working, I compiled, upgraded, flush, removed all cached from var/generated folder

But It's not working. Do you have any clue why it's not working?

This is my code

module.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="MyNameSpace_Paypal" setup_version="1.0.1">
        <sequence>
            <module name="Magento_Paypal" />
        </sequence>
    </module>
</config>

Payflowpro.php

<?php
namespace MyNameSpace\Paypal\Model;

use Magento\Framework\DataObject;
use Magento\Sales\Model\Order;

class Payflowpro extends \Magento\Paypal\Model\Payflowpro
{
    public function addRequestOrderInfo(DataObject $request, Order $order)
    {
        $id = $order->getId();
        //for auth request order id is not exists yet
        if (!empty($id)) {
            $request->setPonum($id);
        }
        $orderIncrementId = $order->getIncrementId();

        //Added ->setData('comment1', $orderIncrementId);   
        //instead of ->setComment1($orderIncrementId)

        $request->setCustref($orderIncrementId)
            ->setInvnum($orderIncrementId)
            ->setData('comment1', $orderIncrementId);
    }
}

di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Paypal\Model\Payflowpro" type="MyNameSpace\Paypal\Model\Payflowpro" />
</config>