fix: handle subject mismatch gracefully

[hperl]

We now redirect to the original request URL if the subjects between the remembered Hydra session and what was confirmed by the login screen does not match.

Related issue(s)

Checklist

• I have read the contributing guidelines.
• I have referenced an issue containing the design document if my change
  introduces a new feature.
• I am following the
  contributing code guidelines.
• I have read the security policy.
• I confirm that this pull request does not address a security
  vulnerability. If this pull request addresses a security vulnerability, I
  confirm that I got the approval (please contact
  [email protected]) from the maintainers to push
  the changes.
• I have added tests that prove my fix is effective or that my feature
  works.
• I have added or changed the documentation.

Further Comments

[codecov]

Codecov Report

Merging #3619 (5383356) into master (0176adc) will decrease coverage by 0.02%.
Report is 1 commits behind head on master.
The diff coverage is 75.00%.

❗ Current head 5383356 differs from pull request most recent head 3eae4ec. Consider uploading reports for the commit 3eae4ec to get more accurate results

@@            Coverage Diff             @@
##           master    #3619      +/-   ##
==========================================
- Coverage   76.19%   76.18%   -0.02%     
==========================================
  Files         133      133              
  Lines       10037    10043       +6     
==========================================
+ Hits         7648     7651       +3     
- Misses       1866     1868       +2     
- Partials      523      524       +1     

Files Changed	Coverage Δ
consent/handler.go	64.81% <75.00%> (-0.26%)	⬇️