qml: Add a recipient when multiple recipients are enabled

Author: johnny9

src/qml/pages/wallet/Send.qml

@@ -38,6 +38,8 @@ PageStack {
             onMultipleRecipientsEnabledChanged: {
                 if (!multipleRecipientsEnabled) {
                     root.wallet.recipients.clearToFront()
+                } else {
+                    root.wallet.recipients.add()
                 }
             }
         }