Add the transaction_id to the payment details when completing the order?

[PILLOWPET]

Current problem

The CompleteOrderAction does not save the transaction id in the Payment details which makes it hard to correlate payment details in Sylius with transactions appearing in the Paypal dashboard.

Proposed solution

In CompleteOrderAction, persist the transaction_id which can be found under $orderDetails['purchase_units'][0]["payments"]["captures"][0]["id"]

I'd be happy to implement this