reporting-engine/report_xml/views/webclient_templates.xml

<?xml version="1.0" encoding="UTF-8" ?>
<odoo>
    <template id="report_xml.assets_backend" inherit_id="web.assets_backend">
        <xpath expr="." position="inside">
            <script type="text/javascript" src="/report_xml/static/src/js/report/action_manager_report.js"/>
        </xpath>
    </template>
</odoo>