This fixes infinite loops that are caused whenever a user is about to solve a 2FA
challenge, but the provider app is disabled at the same time. Since the session
value usually indicates that the challenge needs to be solved before we grant access
we have to remove that value instead in this special case.
As discussed we move all old style classes (OC_FOO_BAR) to legacy.
Then from there we can evaluate the need to convert them back or if they
can be fully deprecated/deleted.
