feat: add Breez *Liquid* SDK funding source (#2681)

Co-authored-by: Pavol Rusnak <pavol@rusnak.io>
Co-authored-by: dni ⚡ <office@dnilabs.com>
Co-authored-by: Vlad Stan <stan.v.vlad@gmail.com>

lnbits/wallets/base.py

@@ -24,6 +24,7 @@ class InvoiceResponse(NamedTuple):
     payment_request: str | None = None
     error_message: str | None = None
     preimage: str | None = None
+    fee_msat: int | None = None
 
     @property
     def success(self) -> bool: