Remove legacy filter from WooCommerce Feature class

[burhandodhy]

Description of the Change

This PR removes the filters code that doesn't exist anymore in WooCommerce and EP. woocommerce_layered_nav_query_post_ids and woocommerce_unfiltered_product_ids was remove in WooCommerce 2.6.

Closes #

How to test the Change

Changelog Entry

Removed - Remove legacy filters woocommerce_layered_nav_query_post_ids, woocommerce_unfiltered_product_ids and ep_wp_query_search_cached_posts code

Credits

Props @burhandodhy

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[felipeelia]

@burhandodhy I'm postponing this to be released in 4.5.0. For that to happen, we will also need to break this into two phases:

1. For 4.5.0 we remove the method's body and replace it with a _doing_it_wrong() or similar
2. For 5.0.0 we really remove them

Both methods have been around for too long now and simply removing them could break someone else's code.