test: expand test suite for verification + OAuth challenge

[hperl]

Related issue(s)

Resolves https://github.com/ory-corp/cloud/issues/5633

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

All modified and coverable lines are covered by tests ✅

Comparison is base (90bdc61) 78.30% compared to head (9236e89) 78.26%.
Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3720      +/-   ##
==========================================
- Coverage   78.30%   78.26%   -0.05%     
==========================================
  Files         347      347              
  Lines       23804    23804              
==========================================
- Hits        18640    18630      -10     
- Misses       3755     3764       +9     
- Partials     1409     1410       +1     

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