How To Bind Custom Text While Adding A Comment In Sales Order View In Magento 2      

<?xml version="1.0"?>

<config xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' xsi:noNamespaceSchemaLocation='../../../../../lib/internal/Magento/Framework/ObjectManager/etc/config.xsd'>

    <type name='Magento\Sales\Controller\Adminhtml\Order\AddComment'>

        <plugin name='order_add_comment' type='Vendor\Extension\Plugin\Adminhtml\Order\AddComment'/>

    </type>

</config>

<?php 
namespace Vendor\Extension\Plugin\Adminhtml\Order;

use Magento\Framework\App\RequestInterface;
use Magento\Backend\Model\Auth\Session;
use Magento\Framework\Exception\NoSuchEntityException;
use Magento\Framework\Exception\InputException;
use Magento\Sales\Api\OrderRepositoryInterface;
use Magento\Sales\Api\Data\OrderStatusHistoryInterface;
use Magento\Sales\Api\OrderStatusHistoryRepositoryInterface;
use Magento\Framework\Registry;
use Magento\Framework\View\Result\PageFactory;
use Magento\Framework\Controller\Result\JsonFactory;
use Magento\Framework\Controller\Result\Redirect;
use Magento\Sales\Model\Order\Email\Sender\OrderCommentSender;
use Magento\Framework\AuthorizationInterface;

class AddComment
{
    public const ADMIN_RESOURCE = 'Magento_Sales::comment';
    public const ADMIN_SALES_EMAIL_RESOURCE = 'Magento_Sales::emails';

    protected $_request;
    protected $authSession;
    protected $orderStatusRepository;
    protected $orderRepository;
    protected $_coreRegistry = null;
    protected $resultPageFactory;
    private $resultJsonFactory;
    protected $orderCommentSender;
    protected $_authorization;
    protected $resultRedirectFactory;

    public function __construct(
        RequestInterface  $request,
        Session $authSession,
        OrderStatusHistoryRepositoryInterface $orderStatusRepository,
        OrderRepositoryInterface $orderRepository,
        Registry $coreRegistry,
        PageFactory $resultPageFactory,
        JsonFactory $resultJsonFactory,
        Redirect $resultRedirectFactory,
        OrderCommentSender $orderCommentSender,
        AuthorizationInterface $authorization
    )
    {
    	$this->authSession = $authSession;
        $this->_request = $request;
        $this->orderStatusRepository = $orderStatusRepository;
        $this->orderRepository = $orderRepository;
        $this->_coreRegistry = $coreRegistry;
        $this->resultPageFactory = $resultPageFactory;
        $this->resultJsonFactory = $resultJsonFactory;
        $this->resultRedirectFactory = $resultRedirectFactory;
        $this->orderCommentSender = $orderCommentSender;
        $this->_authorization = $authorization;
    }

    public function aroundExecute(\Magento\Sales\Controller\Adminhtml\Order\AddComment $subject, callable $proceed)
    {
        $order = $this->_initOrder();
	        if ($order)
                {
	            try
                    {
	                $data = $subject->getRequest()->getPost('history');

	                if (empty($data['comment']) && $data['status'] == $order->getDataByKey('status'))
                        {
	                    throw new \Magento\Framework\Exception\LocalizedException(
	                        __('The comment is missing. Enter and try again.')
	                    );
	                }

	                $order->setStatus($data['status']);
	                $notify = $data['is_customer_notified'] ?? false;
	                $visible = $data['is_visible_on_front'] ?? false;

	                if ($notify && !$this->_authorization->isAllowed(self::ADMIN_SALES_EMAIL_RESOURCE))
                        {
	                    $notify = false;
	                }

	                $comment = trim(strip_tags($data['comment']));
	                $adminusername = $this->authSession->getUser()->getUsername();
	                $history = $order->addStatusHistoryComment($comment.'<br><b>Admin User :</b> '.$adminusername, $data['status']);
	                $history->setIsVisibleOnFront($visible);
	                $history->setIsCustomerNotified($notify);
	                $history->save();

	                $order->save();
	               
	                $this->orderCommentSender->send($order, $notify, $comment);

	                return $this->resultPageFactory->create();
	            }
                    catch (\Magento\Framework\Exception\LocalizedException $e)
                    {
	                $response = ['error' => true, 'message' => $e->getMessage()];
	            }
                    catch (\Exception $e)
                    {
	                $response = ['error' => true, 'message' => __('We cannot add order history.')];
	            }
	            if (is_array($response))
                    {
	                $resultJson = $this->resultJsonFactory->create();
	                $resultJson->setData($response);
	                return $resultJson;
	            }
	      }
              return $this->resultRedirectFactory->create()->setPath('sales/*/');
    }
    
    public function _initOrder()
    {
        $id = $this->_request->getParam('order_id');
        try
        {
            $order = $this->orderRepository->get($id);
        }
        catch (NoSuchEntityException $e)
        {
            return false;
        }
        catch (InputException $e)
        {
            return false;
        }
        $this->_coreRegistry->register('sales_order', $order);
        $this->_coreRegistry->register('current_order', $order);
        return $order;
    }
}