WooCommerce Returns and Warranty Requests 2.6.6

* Tweak - WooCommerce 9.9 compatibility.

* Update Requires headers for WooCommerce compatibility.
* Update to ubuntu-latest to fix QIT tests.

* Tweak - WooCommerce 9.7 compatibility.

* Tweak - PHP 8.4 compatibility.

* Tweak - WordPress 6.7 compatibility.
* Fix - Change the textdomain from `wc_warranty` into `woocommerce-warranty`.
* Fix - Automated translation from WordPress.com.

* Fix - Update notice doesn't go away after clicking the "Run the updater" button.

* Fix - Order cannot be found when searching on RMA page with HPOS mode.

* Add - Guest customer will get a claim warranty link after the order is completed.
* Fix - Display a notice text for non logged-in user when submitting the return form shortcode.
* Update - Security update.

* Update - Security update.
* Tweak - WC tested up to 7.8

Fix - Ensure product variables are WC_Product instances before calling get_meta().