[FIX] mail: use server mail on template

Sending an email wasn't taking the outgoing mail server into account.
Adding it in the 'account_invoice_send_views' to use it in the wizard.

opw-2030717

closes odoo/odoo#34593

Signed-off-by: Nicolas Lempereur (nle) <nle@odoo.com>

addons/account/wizard/account_invoice_send_views.xml

@@ -13,6 +13,7 @@
                     <field name="composer_id" invisible="1"/>
                     <field name="invoice_ids" invisible="1"/>
                     <field name="email_from" invisible="1" />
+                    <field name="mail_server_id" invisible="1"/>
                     <div name="option_print">
                         <field name="is_print" />
                         <b><label for="is_print"/></b>