tapchannel: compare asset id of htlc records with quote

In this commit we use the previously defined helper to fetch the asset
ID of the accepted quote, then we compare it with the asset ID of each
HTLC. This is done as an extra strict check to guard against HTLC and
RFQ asset ID mismatch, which can lead to malicious behavior where a
quote for a different asset is being accounted for when accepting an
asset HTLC.

tapchannel/aux_invoice_manager.go

@@ -198,6 +198,19 @@ func (s *AuxInvoiceManager) handleInvoiceAccept(_ context.Context,
 	// Convert the total asset amount to milli-satoshis using the price from
 	// the accepted quote.
 	rfqID := htlc.RfqID.ValOpt().UnsafeFromSome()
+
+	assetID, err := s.assetIDFromQuote(rfqID)
+	if err != nil {
+		return nil, fmt.Errorf("could not extract assetID from "+
+			"quote: %v", err)
+	}
+	for _, v := range htlc.Balances() {
+		if v.AssetID.Val != *assetID {
+			return nil, fmt.Errorf("mismatch between htlc asset " +
+				"ID and rfq quote asset ID")
+		}
+	}
+
 	assetRate, err := s.priceFromQuote(rfqID)
 	if err != nil {
 		return nil, fmt.Errorf("unable to get price from quote with "+