routing: remove second chance logic

[joostjager]

Implemented to show the change set.

Fixes #6883

[joostjager]

The unit test TestSendPaymentPrivateEdgeUpdateFeeExceedsLimit is failing because of the change. It's interesting though, because it isn't easy to make the test pass. Without 2nd chance logic, the failure-generating node and its incoming peer are penalized, which also blocks other routes coming in through that peer, but going out through a different channel.

The first thought may be "let's penalize the outgoing pair", because that's the channel for which the fee was incorrect. This however doesn't account for the scenario where the inbound node forwards an incorrect htlc amount and should be penalized.