Drop unused order state-machine transtion to fully refunded

[diimpp]

order->state = fully_refunded is defined in the plugin, but never used by anything.

Besides, if such transition should exist, then it should be named refunded as partional refund state is called partially_refunded.

[GSadee]

Hello @diimpp! If I see correctly, this transition is used by OrderFullyRefundedStateResolver, which is called in RefundPaymentProcessManager after UnitsRefunded event. So, removing this transition could break the current behaviour and some end applications. Because of that, I'm closing this PR for now, but feel free to reopen it or comment here if you still think that this change is valid.

[diimpp]

@GSadee Hi!

this state is not used by OrderFullyRefundedStateResolver, name of this resolver is misleading and it operates on OrderPaymentState, not OrderState.

https://github.com/Sylius/RefundPlugin/search?q=fully_refunded

OrderState:fully_refunded is an artifact from old big refactor at #123 and not used anywhere in the app. This state in unreachable by the app.

[GSadee]

Ok, my mistake, I had a wrong look at the interface this transition is going from.

[GSadee]

@diimpp could you add some note in UPGRADE file about removing this state and transition?

[diimpp]

Thanks @GSadee !

[GSadee]

Thank you, Dmitri! 🥇