Add note about network permission

android/app/src/main/java/com/futo/futopay/PaymentManager.kt

@@ -68,7 +68,7 @@ class PaymentManager {
             catch(ex: Throwable) {
                 Log.e(TAG, "startPayment failed", ex);
                 scope.launch(Dispatchers.Main){
-                    UIDialogs.showGeneralErrorDialog(_fragment.requireContext(), "Failed to get required payment data", ex);
+                    UIDialogs.showGeneralErrorDialog(_fragment.requireContext(), "Failed to get required payment data (did you grant the app network permission?)", ex, onOk = { _listener.onCancel() });
                 }
             }
         }