[FIX] {website_}event: fix event tour

Before this commit, the user got a traceback saying:
```txt
TypeError: Cannot read properties of undefined (reading 'apply')
    at EventAdditionalTourSteps._get_website_event_steps
```
the reason of that issue is because a [recent generic change reviews](#125716)
`patch` function and so `this._super` no longer exists and has to be
replace by `super` as we extend a method of a class extended.

This commit adapts the additional steps adding via `patch` function
to be able to add those steps and start the tour as expected.

closes odoo/odoo#142653

Signed-off-by: Warnon Aurélien (awa) <awa@odoo.com>

addons/event/static/src/js/tours/event_steps.js

@@ -3,7 +3,7 @@
 class EventAdditionalTourSteps {
 
     _get_website_event_steps() {
-        return [false];
+        return [];
     }
 
 }

addons/website_event/static/src/js/tours/event_tour.js

@@ -8,9 +8,9 @@ import { patch } from "@web/core/utils/patch";
 
 patch(EventAdditionalTourSteps.prototype, {
 
-    _get_website_event_steps: function () {
-        this._super.apply(this, arguments);
-        return [{
+    _get_website_event_steps() {
+        return [
+            ...super._get_website_event_steps(), {
                 trigger: '.o_event_form_view button[title="Unpublished"]',
                 content: markup(_t("Use this <b>shortcut</b> to easily access your event web page.")),
                 position: 'bottom',