Stringify errors that get sent to notifications (#3393)

Signed-off-by: Sebastian Malton <sebastian@malton.name>

src/renderer/components/notifications/notifications.tsx

@@ -88,7 +88,7 @@ export class Notifications extends React.Component {
   getMessage(notification: Notification) {
     let { message } = notification;
 
-    if (message instanceof JsonApiErrorParsed) {
+    if (message instanceof JsonApiErrorParsed || message instanceof Error) {
       message = message.toString();
     }