Bug: Guests cannot use side entrance locallogin

[christianwolters]

Describe the bug
Guests cannot use local login on side entrance page.

To Reproduce
Steps to reproduce the behavior:

1. Activitate local login and hide local login from default login page
2. Login as guest
3. Go to local login page ('side entrance')
4. One gets redirected to core login page.

Expected behavior
Guests should be able to login via side entrance, as there is no other way for them to log into a local account.

Additional context
Probably regression from core login port to BU local login.