pos/pos_loyalty/views/res_partner_view.xml

<?xml version="1.0"?>
<odoo>
    <record id="partner_property_form_view" model="ir.ui.view">
        <field name="name">partner.property.form</field>
        <field name="model">res.partner</field>
        <field name="inherit_id" ref="point_of_sale.view_partner_property_form"/>
        <field name="arch" type="xml">
            <button name="%(point_of_sale.action_pos_pos_form)d" position="before">
                <button class="oe_stat_button" type="action" name="%(point_of_sale.action_pos_pos_form)d" 
                    context="{'search_default_partner_id': active_id,'default_partner_id': active_id}"
                    attrs="{'invisible': ['|', ('customer', '=', False), ('pos_order_count', '=', 0)]}"
                    icon="fa-star">
                    <field name="loyalty_points" widget="statinfo"/>
                </button>
            </button>
        </field>
    </record>
</odoo>