Consolidate "receive payment" snippets, expose invoice

snippets/react-native/receive_payment.ts

@@ -2,9 +2,11 @@ import { receivePayment } from '@breeztech/react-native-breez-sdk'
 
 const exampleReceiveLightningPayment = async () => {
   // ANCHOR: receive-payment
-  const invoice = await receivePayment({
-    amountMsat: 3000000,
+  const receivePaymentResponse = await receivePayment({
+    amountMsat: 3_000_000,
     description: 'Invoice for 3000 sats'
   })
+
+  const invoice = receivePaymentResponse.lnInvoice
   // ANCHOR_END: receive-payment
 }