Refine failed refund notes

[jrodger]

We have some basic handling of failed refunds added in #411.

After issuing a refund, the refund can fail at a later date. For example, the card used for the purchase could have expired. To handle this we send a refund failed webhook which adds a note to the order:

@RadoslavGeorgiev and @vbelolapotkov rightly pointed out that the notes don't make complete sense after a failure has occurred. We tell the merchant that the refund was successful, and then the next note says it wasn't.

There are also some questions about how we want to handle this more generally:

• Should the order status be moved back to "Processed"?
• Do we need to let WooCommerce know that the refund didn't actually happen?
• Does this happen frequently (to help us decide the priority of this issue)?
• Is there any prior art here?

[allendav]

Is there any prior art here?

Please check if this can happen on Square, PayPal Checkout, Amazon and let's come up with a common, consistent strategy (and Stripe extension too) since merchants tend to install more than one payment gateway (hopefully ours)

fyi @bmccotter @LCmry

[vbelolapotkov]

There are many questions on this issues we'd need to resolve first before proceed with implementation. AFAIR it's tricky one due to the async nature of refund failures and unreliable delivery of forwarded hooks, or in the case of successful refund there won't be any following hooks at all. Anyway, more in-depth exploration is necessary here.

[zmaglica]

I believe that this issue has enough context, and it can be moved from the Engineering review queue to the Ready of prioritization. If additional feedback or research is needed, the dedicated person can be assigned to this issue to perform additional research or reach out to the people who will have more context.

This is the part of the Gamma backlog porter duty to reduce the number of the issues in the Engineering review column.

[naman03malhotra]

@htdat can you please check it and see if it is still relevant, then we can loop in product and design for the next steps.

[RadoslavGeorgiev]

I could have been fixed by #3965

[htdat]

@htdat can you please check it and see if it is still relevant, then we can loop in product and design for the next steps.

I tested with the latest version 6.2.2 - screenshot, and notes are still the same as what James mentioned above.

Moving this issue to "Product review" queue.

It could have been fixed by #3965

PR #3965 is to remove WC_Order_Refund attached to the order when a failing refund is caught up. It does not change note content.