fix: amount not passed in request from zero amount payment screen (#1656)

frontend/src/screens/wallet/send/ZeroAmount.tsx

@@ -43,6 +43,9 @@ export default function ZeroAmount() {
           headers: {
             "Content-Type": "application/json",
           },
+          body: JSON.stringify({
+            amount: +amount * 1000,
+          }),
         }
       );
       if (!payInvoiceResponse?.preimage) {