WooCommerce Waitlist 2.4.15

* Fix: sortable admin column query not working for all values, updated to be simpler and handle edge cases
* Fix: added update function for waitlist counts when using the update counts tool

* Fix: user deletion, when processed on the frontend, was not properly removing users from the waitlists

* Fix: Email not always being added to events waitlist form for logged in users causing silent error
* Added: Various fixes to comply with PHPCS
* Added: Filters to hide notices on the frontend (wcwl_show_notice_on_frontend)
* Added: Altered frontend flow to allow join/leave buttons to show without having to dismiss notices
* Added: Action hook to output custom HTML before submit button for waitlist forms (wcwl_before_form_submit_button)
* Added: Action hook to apply additional validation to waitlist join/leave requests (wcwl_process_waitlist_request_start)
* Added: Product ID/object to various frontend filters to allow for easier customisation
* Added: Deprecation notice for old supported products filter
* Added: Sorting products by waitlist count in the admin will now show all products (previously it did not return those with no waitlist data)

* Fix: Updated function to calculate count totals to target variable products as well

* Fix: Double Opt in not working for all product types

* Fix: Fatal error on new user register due to refactoring core plugin file

Fix: Deprecated PHP notice for order of function parameters

Fix: Waitlist counts for variations not showing correctly

Added: Compatibility for HPOS

* Fix: Update to translations template file