WooCommerce API Manager 3.4.2

* Dev: Add `wc_api_manager_email_product_heading` filter hook to filter the product heading in HTML order complete emails
* Dev: Add `wc_api_manager_email_product_title_prefix` filter hook to filter the product title prefix in plain text order complete emails
* Dev: Add `wc_api_manager_my_account_product_title_heading` filter hook to filter the product title heading in my account API keys
* Dev: Add `wc_api_manager_my_account_hide_duplicate_products` filter hook to toggle showing duplicate products to be visible in my account API keys

* Fix: Update templates to avoid incorrect usage of escaping functions

* Dev: Add filter to toggle whether to update the API Resource expires value in orders after updating the expiration value in product variations