[vseth-components] Non-admin login does not work

In the old UI it was possible to log in as non-admin even if you are an admin by pressing shift while submitting the login form. This is really useful to quickly check whether something works/is correctly displayed for non-admin users if we get a report of a problem. It also makes testing new features in staging way easier (e.g. I wanted to check how inappropriate answers are displayed to users).

It would be nice to have this feature preserved.