WooCommerce WishLists 2.3.1

* Update: Only perform validation when moving from a list to the cart via the woocommerce_add_to_wishlist_validation filter.
* Update: Add additional content to the wishlist share email.
* Update: Add {wishlist_url} to the wishlist share email.
* Update: Add {wishlist_email} to the wishlist share email.
* Compatibility: Add compatibility with HPOS.
* Security: Updated reflected text in templates and emails to be escaped.

* Update: Correct spelling of filter, wc_wishlists_udpate_list_args
* Update: Added woocommerce_add_to_cart_validation before an item is added to the cart.
* Update: Added check for Google trying to follow the add to wishlist link.
* Update: If for some reason an invalid product ID is passed to the wishlist handler, it will now just ignore it.
* Update: Remove old WC extension update functions.
* Fix: Send the product URL through the woocommerce_get_product_permalink filter in the view template.

* Fix: Check if the product is available before calling methods on it. Fixes issues with Divi incorrectly causing WooCommerce actions to fire on non product pages.
* Update: If the filtered template hook is empty do not add the wishlist form.
* Update: Use $_REQUEST when editing the list for checking for the list id.