Enriched error message during debugging

[bilfeldt]

When the plugin was unable to find any pick-up points then a text "Shipping to closest pick-up point" is shown. This can be due to a few different reasons and it is hard to find out why this is.

If debugging is enabled for WooCommerce shipping (WooCommerce->Settings->Shipping->Shipping options->Enable debug mode) then some debug info about why no pickup points was found needs to be added.

This can either be added to the rendering of the select option:

• Shipping to closest pick-up point (Debug: No subscription)
• Shipping to closest pick-up point (Debug: Unexpected error response)

Or in the Debug notice bar at the top: