Small adjustment: Disabled authentication should automatically hide the Sign in / Register Buttons

Since its possible to disable all forms of authentication for end-users and allow them to use the app anonymous the "Sign in / Register" buttons should then not be shown, since they only show an empty text status message and might confuse visitors. 

<img width="602" height="108" alt="Image" src="https://github.com/user-attachments/assets/6d044ed7-5dca-4d37-8486-a2a2dbb67df4" />