Use webhooks for refund transactions

[RomanovM]

When I made a full or partial refund from the NopCommerce Admin panel for an order placed using Square as method of payment, the refund request is received by square and create the refund, but the status of that fund is PENDING on our square account, and that is received by NopCommerce, but the order is not marked as refunded and the refunded amount is still 0 at NopCommerce side (our website). This error message is logged :
"Error refunding order #285320. Error: Error 0: Refund is PENDING"

And an order note is added with the same information.

After a few minutes, the status of the refund changed from PENDIND to PROCCESED at the square side and the customer eventually receive the money, but the transaction is not marked as refunded.

According to Square they might send some notification when some events occurs like a refund status change, but we need to subscribe to such notifications and configure them by enter a webhook URL like https://ourwebsite.com/webhooks

You can find more info here:

https://developer.squareup.com/docs/webhooks-api/subscribe-to-events

Source: https://www.nopcommerce.com/en/boards/topic/90456/does-nopcommerce-square-plugin-support-webhooks