Identify hydra email verfication problem

[kghost]

Note: This is not a fix, this is a POC to identify the problem

Related issue(s)

#3358
#3320

Problem: When completing a sign up coming from hydra (registration flow with login_challenge), even with show_verification_ui configured in post registrition hook, it doesn't jump to verfication page, but logined to hydra direct, and succesfully grant an oauth2 token.

This breaks our security model which relies our private email account.

This patch helps to identify the problem, it work as expected, when completing a sign up, it redirects to verfication page.

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.

[CLAassistant]

All committers have signed the CLA.