[FIX] product_email_template: use proper parameters

`custom_layout` should be set as a context key, otherwise it crashes at
creation because of non-existing field.

opw-2146695
opw-2149726

closes odoo/odoo#41238

X-original-commit: f9837eb08a316965057fe239f434b1c6d5c0196c
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>

addons/product_email_template/models/account_move.py

@@ -14,7 +14,9 @@ class AccountMove(models.Model):
                 invoice.message_subscribe([invoice.partner_id.id])
             for line in invoice.invoice_line_ids:
                 if line.product_id.email_template_id:
-                    invoice.message_post_with_template(line.product_id.email_template_id.id, composition_mode='comment', custom_layout='mail.mail_notification_light')
+                    invoice.with_context(custom_layout="mail.mail_notification_light").message_post_with_template(
+                        line.product_id.email_template_id.id, composition_mode="comment"
+                    )
         return True
 
     def post(self):