[FIX] sale: sale_tour wait on partner creation step

Steps to reproduce:
- install sales
- go into debug mode
- dev tools > start tour > sale_tour

Previous behavior:
tour would fail after creating the "Agrolait" partner.
the test would not wait for the return value of the
customer selection.

Current behavior:
the test waits for the customer to be fully selected and does not fail.

closes #40569
opw-2091797

closes odoo/odoo#43172

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

addons/sale/static/src/js/tour.js

@@ -37,7 +37,7 @@ tour.register('sale_tour', {
     in_modal: false,
 }, {
     trigger: ".o_field_x2many_list_row_add > a",
-    extra_trigger: ".o_sale_order",
+    extra_trigger: ".o_field_many2one[name='partner_id'] .o_external_button",
     content: _t("Click here to add some products or services to your quotation."),
     position: "bottom",
 }, {