fix reading updater token for web updater

the previously called endpoint returns exactly one value, no JSON
structure

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

apps/updatenotification/src/components/UpdateNotification.vue

@@ -406,7 +406,7 @@ export default {
 					const hiddenField = document.createElement('input')
 					hiddenField.setAttribute('type', 'hidden')
 					hiddenField.setAttribute('name', 'updater-secret-input')
-					hiddenField.setAttribute('value', data.token)
+					hiddenField.setAttribute('value', data)
 
 					form.appendChild(hiddenField)