Successful payments should return amounts of payments not InfoResponse

[Kodylow]

Currently clientd returns an InfoResponse for success when it receives ecash as part of a payment, this should be updated so that methods like pay, await_invoice, claim tweaked, etc. return the amounts that were used as part of the method. It's hard to see how much you paid or received with the info response, I just used it originally because I was mirroring the cli but for http that info response isn't useful besides /info