WooCommerce Waitlist 2.4.11

* 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

* Fix: Waitlist mailouts not always sending for variations when setting stock status

* Fix: Updates for security audit
* Fix: Double opt-in email escaping allows '+' symbol
* Added: Optional filter to add extra emails to all waitlist mailouts: 'wcwl_mailout_extra_email_addresses'