b9a81cd03e
We were already reserving wallet addresses for full channels. Now we also do the same for imported channel backups. (but not for onchain, as we don't have enough info for that) Without this, if the same seed is used on multiple devices (with each device having its own set of LN channels), the wallet instances will reuse keys (specifically the payment_basepoint, which for static_remotekey chans is used as the to_remote output). Now with this change, at least if the wallet instances have imported channel backups of each other, this reuse is avoided.