Implement latest dual-funding signature retransmission

Please prioritize implementing the latest reconnection logic for interactive-tx specified in https://github.com/lightning/bolts/pull/1289. This is blocking the merge of the splicing PR right now, even though this reconnection mechanism is fully supported by LDK (for both dual-funding and splicing) and is supported by `cln` for splicing, but not for dual-funding (which is inconsistent as there should be code sharing for this part of the state machine).

Once implemented, we can finally move dual-funding out of the "experimental" features and activate it by default. And once the last cross-compatibility issues for splicing are fixed (see #8705) we can also finally get splicing activated on the network and merged to the BOLTs!

@niftynei @ddustin