magento-test/app/code/Magento/Newsletter/etc/frontend/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\Url\SecurityInfo">
        <arguments>
            <argument name="secureUrlList" xsi:type="array">
                <item name="newsletter_manage" xsi:type="string">/newsletter/manage/</item>
            </argument>
        </arguments>
    </type>
    <type name="Magento\Framework\View\Element\Message\MessageConfigurationsPool">
        <arguments>
            <argument name="configurationsMap" xsi:type="array">
                <item name="localizedSubscriptionErrorMessage" xsi:type="array">
                    <item name="renderer" xsi:type="const">\Magento\Framework\View\Element\Message\Renderer\BlockRenderer::CODE</item>
                    <item name="data" xsi:type="array">
                        <item name="template" xsi:type="string">Magento_Newsletter::messages/localizedSubscriptionErrorMessage.phtml</item>
                    </item>
                </item>
            </argument>
        </arguments>
    </type>
</config>