fix: broken route translation for ln invoices to domain

[vindard]

Description

Routes hints from ln invoices were not being translated to our domain properly and so were returning undefined values when converted back to pass into the lightning library's payViaPaymentDetails method.

The end result of this bug was that we weren't able to pay any invoices where there were route hints and where the final destination was a private node/channel.

Affected wallets for receiving from us that will now work again:

• Phoenix
• Breez
• Blixt
• SBW
• Chivo
• *Muun (there's still an open fee probe issue here, see payment failure with wallet that open channels on the fly #32)