[FIX] purchase: Adding PO on refund vendor bill

The function  _prepare_invoice_line_from_po_line has not been
designed to compute in a right the quantity for a  line in an
in_refund invoice. So it has no sens to display the field purchase_id
for a refund vendor bill.

Closes #23095

opw:816717

addons/purchase/views/account_invoice_views.xml

@@ -59,7 +59,7 @@
         <field name="inherit_id" ref="account.invoice_supplier_form"/>
         <field name="arch" type="xml">
             <field name="reference" position="after" >
-                 <field name="purchase_id" attrs="{'readonly': [('state','not in',['draft'])], 'invisible': [('state', '=', 'purchase')]}" class="oe_edit_only"
+                 <field name="purchase_id" attrs="{'readonly': [('state','not in',['draft'])], 'invisible': ['|', ('state', '=', 'purchase'), ('type', '=', 'in_refund')]}" class="oe_edit_only"
                     options="{'no_create': True}"/>
             </field>
             <xpath expr="//field[@name='invoice_line_ids']/tree/field[@name='company_id']" position="after">