contract/contract_mandate/views/contract_view.xml

<?xml version="1.0"?>
<odoo>

    <record id="account_analytic_account_payment_form" model="ir.ui.view">
        <field name="model">account.analytic.account</field>
        <field name="inherit_id" ref="contract_payment_mode.account_analytic_account_payment_form" />
        <field name="arch" type="xml">
            <field name="payment_mode_id" position="after">
                <field name="mandate_id"
                domain="[('partner_id', '=', commercial_partner_id), ('state', '=', 'valid')]"
                attrs="{'invisible': ['|', ('mandate_required', '=', False), ('recurring_invoices', '=', False)]}"/>
                <field name="commercial_partner_id" invisible="1"/>
                <field name="mandate_required" invisible="1"/>
            </field>
        </field>
    </record>

</odoo>