Fixed bugs in specific environments/updated page builder

【Contents of the fix】
■【macOS Big Sur】 Fixed a bug that the YouTube video in the top page header content does not play in Chrome browser.
■Page builder update (compatible with WordPress 5.5)

The following are the files that have been modified for this update.
【Modified file】
functions/custom_page_link.php
functions/update_notifier.php
js/jquery.mb.YTPlayer.min.css
js/jquery.mb.YTPlayer.min.js
languages/ja.mo
languages/ja.po
pagebuilder/assets/admin/css/admin.css
pagebuilder/assets/admin/js/admin.js
pagebuilder/assets/admin/js/editor.js
pagebuilder/assets/admin/js/repeater.js
pagebuilder/assets/admin/js/slider.js
pagebuilder/modules/googlemap.php
pagebuilder/modules/slider.php
pagebuilder/modules/tab.php
pagebuilder/pagebuilder.php
style.css