[FIX] website_slides: fix video not loaded in fullscreen web content

Issue

	- Create a content in a course with type "web page"
	- Access it frontend and add a "text - image" block, edit the image as a video - save
	- The video is displayed correctly
	- Go into full-screen

	The video is not displayed at all.

Cause

	The content is added after the page and page widgets are started

Solution

	Trigger the widgets start method

OPW-2290233

closes odoo/odoo#54190

X-original-commit: 0f93240e4979479ab281ca49e8703b325c4b83f0
Signed-off-by: Jason Van Malder (jvm) <jvm@odoo.com>

addons/website_slides/static/src/js/slides_course_fullscreen_player.js

@@ -573,6 +573,9 @@ odoo.define('website_slides.fullscreen', function (require) {
                 var $wpContainer = $('<div>').addClass('o_wslide_fs_webpage_content bg-white block w-100 overflow-auto');
                 $(slide.htmlContent).appendTo($wpContainer);
                 $content.append($wpContainer);
+                this.trigger_up('widgets_start_request', {
+                    $target: $content,
+                });
             }
             return Promise.resolve();
         },