Include payment hash in Bolt12Invoice reply path

Instead of using OffersContext::Unknown for the Bolt12Invoice reply path
use OffersContext::InboundPayment to include the payment hash.
OffersContext::Unknown will be removed in another commit.

Author: jkczyz

lightning/src/ln/channelmanager.rs

@@ -9118,7 +9118,11 @@ where
 				)?;
 				let builder: InvoiceBuilder<DerivedSigningPubkey> = builder.into();
 				let invoice = builder.allow_mpp().build_and_sign(secp_ctx)?;
-				let reply_paths = self.create_blinded_paths(OffersContext::Unknown {})
+
+				let context = OffersContext::InboundPayment {
+					payment_hash: invoice.payment_hash(),
+				};
+				let reply_paths = self.create_blinded_paths(context)
 					.map_err(|_| Bolt12SemanticError::MissingPaths)?;
 
 				let mut pending_offers_messages = self.pending_offers_messages.lock().unwrap();