WooCommerce Order Status Manager 1.15.4

* Fix - The `wc-checkout-draft` status has been automatically updated to change its "Paid" setting to "Orders with this status require payment". This fixes issues with block checkout for some gateways.

* Fix - Ensure Font Awesome icons are loaded on orders list page when HPOS is enabled
* Fix - Ensure order line items appear in custom emails that are dispatched when a new order is created
* Fix - Address PHP warnings when emails are sent
* Fix - Ensures custom image icons are kept in place when status changes are made

Misc - Add compatibility for WooCommerce High Performance Order Storage (HPOS)

* Misc - Require PHP 7.4 and WordPress 5.6