[16.0][IMP] purchase_last_price_info_ext: Improve traceback

[unaiberis]

self.with_context(skip_update_price_unit=True).price_unit = price File "/opt/odoo/v16/core/odoo/fields.py", line 1325, in set records.write({self.name: write_value}) File "/opt/odoo/v16/github/oca/server-tools/auditlog/models/rule.py", line 396, in write_full result = write_full.origin(self, vals, **kwargs) File "/opt/odoo/v16/github/avanzosc/odoo-addons/purchase_order_line_update_seller/models/purchase_order_line.py", line 36, in write result = super().write(values) File "/opt/odoo/v16/github/avanzosc/odoo-addons/purchase_last_price_info_ext/models/purchase_order_line.py", line 17, in write product.set_product_last_purchase(line.order_id.id) AttributeError: 'product.product' object has no attribute 'set_product_last_purchase'