abandonned authentication attempt interferes leads to mix-up of issuer contexts
following the bugfix in #1939 (closed), the following scenario remains broken:
- Browse to Issuer 1
- Get redirected to login form
- Don't touch login form, browse to Issuer 2
- Get redirected to login form again
- This time, actually login
- LLNG sends you to issuer 1
This works if issuer 1 and issuer 2 are the same type (CAS, OIDC or SAML), but not if issuer 1 and issuer 2 are different types.