cli: enrich transfer errors with PFS error details

The plain message that the PFS returned an error is not helpful for the
user. Therefore the error details get appended in case they exist.

raiden-cli/src/routes/payments.ts

@@ -43,7 +43,6 @@ async function doTransfer(this: Cli, request: Request, response: Response, next:
       request.body.amount,
       { paymentId: request.body.identifier },
     );
-    this.log.info(`Transfer key: ${transferKey}`);
     await this.raiden.waitTransfer(transferKey);
     const newTransfer = await this.raiden.transfers$
       .pipe(first(({ key }: RaidenTransfer) => key === transferKey))
@@ -53,7 +52,8 @@ async function doTransfer(this: Cli, request: Request, response: Response, next:
     if (isInvalidParameterError(error)) {
       response.status(400).send(error.message);
     } else if (isConflictError(error)) {
-      response.status(409).send(error.message);
+      const pfsErrorDetail = error.details?.errors ? ` (${error.details.errors})` : '';
+      response.status(409).send(error.message + pfsErrorDetail);
     } else {
       next(error);
     }