newsupernova/vendor/magento/module-tax/etc/adminhtml/di.xml

<?xml version="1.0"?>
<!--
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
-->
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <type name="Magento\Framework\Notification\MessageList">
        <arguments>
            <argument name="messages" xsi:type="array">
                <item name="tax" xsi:type="string">Magento\Tax\Model\System\Message\Notifications</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Tax\Model\System\Message\Notifications">
        <arguments>
            <argument name="notifications" xsi:type="array">
                <item name="roundingErrors" xsi:type="object">Magento\Tax\Model\System\Message\Notification\RoundingErrors</item>
                <item name="discountErrors" xsi:type="object">Magento\Tax\Model\System\Message\Notification\DiscountErrors</item>
                <item name="applyDiscountOnPrices" xsi:type="object">Magento\Tax\Model\System\Message\Notification\ApplyDiscountOnPrices</item>
            </argument>
        </arguments>
    </type>
</config>