follow-up invoice changes: fix kivy RequestDialog

follow-up 719b468eee

electrum/gui/kivy/uix/dialogs/request_dialog.py

@@ -186,7 +186,9 @@ class RequestDialog(Factory.Popup):
         help_texts = self.app.wallet.get_help_texts_for_receive_request(req)
         address = req.get_address() or ''
         URI = self.app.wallet.get_request_URI(req) or ''
-        lnaddr = req.lightning_invoice or ''
+        lnaddr = ""
+        if req.is_lightning():
+            lnaddr = self.app.wallet.get_bolt11_invoice(req)
         self.status = self.app.wallet.get_invoice_status(req)
         self.status_str = req.get_status_str(self.status)
         self.status_color = pr_color[self.status]