"Start Page" does not default to a sane value after being cleared

Steps to reproduce

Navigate to Settings > Defaults > Start Page and clear the value set
Observe the field is now blank
Open a private browsing window and attempt to login to ITFlow
Observe that the login "loops" - it doesn't actually, it's just that you're not directed anywhere

We should enforce a value being set for Start Page, either through HTML validation or catching and replacing a blank value in the POST process.

wrongecho I think making a dropdown with all avail pages, like this you can't have the field blank or set to non-existing page.

Selectable Options but has the option to input a custom value

This has been fixed here: