* - implement Node on different Types
* - update class-customers to return arrays for edges and nodes
- move id resolver from product-attribute interface to the specific types
* - return empty arrays for edges/nodes for coupon connections
- update test to check for falsy vs null
* - remove manual registration of the `Product` Interface
- register the fields to the Product Interface
* - fix code style
* - fix code style
* - no longer pass type registry to Product::register_interface()
* - use post type registry to register the Product type as an Interface
* WPGraphQL v1.13.x support added.
* WPGraphQL v1.13.x support added.
* fix: filter corrected.
* fix: Needed code restored
* fix: Needed code restored
* parent field no longer overwritten
* chore: WPCS compliance met.
Co-authored-by: Geoff Taylor <geoff@axistaylor.com>
