Multiple bug fixes

【Contents of the fix】
■Corresponded to the specification change of social button type 5 (official button) “Facebook Like Button”.
■Removed “Google+” from the social button settings.
■Fixed an error related to the login judgment in the comment section.
■Fixed a bug that the modal display of products and galleries does not work on WordPress 5.6.
(jQuery plugin has been updated to the latest version due to changes in WordPress 5.6)
■【Mac】Fixed a bug in which Japanese and European characters were displayed with different thickness when using some fonts.
■Changed Facebook OGP setting from old specification (fb:admins) to new specification (fb:app_id).
※Please refer to the following article about how to get “fb:app_id” (application ID).
 How to get the fb:app ID required for Facebook OGP settings
■OGP Tag Optimization

The following are the files that have been modified for this update.

【Modified file】
admin/theme-options.php
comments.php
editor-style-01.css
functions/ogp.php
functions/seo.php
japanese.css
js/imagelightbox.min.js
languages/ja.mo
languages/ja.po
sns_btn_btm.php
sns_btn_top.php
style.css