[FIX] mass_mailing, website: add markup in tour content

Current behavior before PR:
  - HTML tags are displayed in the onboarding tour.

Desired behavior after PR is merged:
  - Display the HTML tag effects instead of showing it in the onboarding tour.

After the https://github.com/odoo/odoo/pull/107618 web_tour was converted into
Owl, 'markup' was required to show the html tag effect instead of htm tags.

Related Enterprise PR-https://github.com/odoo/enterprise/pull/53893

Task-3457112

closes odoo/odoo#149957

X-original-commit: c26ba2943317e82388bc05adfd64fa729923a86b
Related: odoo/enterprise#54622
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>

addons/website/static/tests/tours/homepage_edit_discard.js

@@ -1,5 +1,6 @@
 /** @odoo-module **/
 
+import { markup } from "@odoo/owl";
 import wTourUtils from "@website/js/tours/tour_utils";
 
 // TODO remove this test; it is badly written: you just have to change the fact
@@ -13,7 +14,7 @@ wTourUtils.registerWebsitePreviewTour('homepage_edit_discard', {
 }, () => [{
     trigger: "#oe_snippets button[data-action=\"cancel\"]:not([disabled])",
     extra_trigger: "body:not(:has(.o_dialog))",
-    content: "<b>Click Discard</b> to Discard all Changes.",
+    content: markup("<b>Click Discard</b> to Discard all Changes."),
     position: "bottom",
 }, {
     trigger: "iframe body:not(.editor_enable)",