The user impersonation documentation just mentions

control the redirection target route via target_route

Now, given that Twig’s impersonation_exit_path and impersonation_exit_url have an exitTo parameter but not impersonation_path nor impersonation_url, it looks like target_route should only be used when starting an impersonation. However it is currently also used when exiting, which means that if you configured one, an exitTo argument wouldn’t have any effect.

Based on this assumption, this PR ignores target_route when exiting impersonation.

Since exitTo will now work with target_route this PR technically breaks BC, but since this behavior was broken I’m not sure it needs to be considered.