Update routes.py

Clicking 'back to results' now also works if no active session cookie present.

requested review from @c.fortmanngrote

assigned to @c.fortmanngrote

mentioned in commit f8d91f4b

merged

added Review label

removed Review label

assigned to @bertels

unassigned @c.fortmanngrote

requested review from @bertels

assigned to @c.fortmanngrote

unassigned @bertels

removed review request for @c.fortmanngrote

added Review label