Multiple bug fixes / support for WP5.8 widget block editor

【Contents of the fix】
■Fixed a bug in which alerts were not displayed correctly when items were added to the cart with required fields not selected in the product options.
■Fixed an issue where setting the overlay transparency of the product category page header to “0” was not reflected.
■Fixed a bug in the Gutenberg editor (block editor) that prevented image blocks from being centered.
■Fixed a bug in the Gutenberg editor (block editor) that caused the layout to collapse depending on the placement of the last block.
■Fixed a bug that caused a PHP 7.4 error in the Pinterest share button when the eye catching image was not set.
■【iPhone】Fixed a problem where a single tap on a thumbnail does not lead to the link destination.
(This has resulted in a specification that disables the hover effect on mobile devices.)
■Changed to not show the header member menu and cart contents when mouse-over on mobile devices.
■Support for the WordPress 5.8 widget block editor

【Modified files

functions/acceleration.php
js/functions.js
languages/ja.mo
languages/ja.po
template-parts/header-login.php
template-parts/header-view-cart.php
template-parts/page-header.php
template-parts/sns-btn-btm.php
template-parts/sns-btn-top.php
footer.php
functions.php
page.php
page__ranking.php
single-news.php
single.php
style.css