Fix user creation as root

[ThomasLaPiana]

Closes #2077

Code Changes

• add a test to catch the 403 caused by creating a user as root
• add the fix

Steps to Confirm

• Run nox -s dev
• Login as the root user
• Create a user, assert the user is created
• Edit a user, assert the user's data is updated
• Login as the created user, assert that the user is able to act in some way

Pre-Merge Checklist

• All CI Pipelines Succeeded
• Documentation:
  • documentation complete, PR opened in fidesdocs
  • documentation issue created in fidesdocs
• Issue Requirements are Met
• Relevant Follow-Up Issues Created
• Update CHANGELOG.md

Description Of Changes

This regression was caused by the removal of the fideslib references from our codebase. fideslib was designed to have a common override pattern (with safe backstop) for the verify_oauth_client API dependency — which is not being overridden correctly now that the code is in the main codebase. This PR switches out the version of that method designed to be overloaded with the current method in use by the rest of the codebase.

[ThomasLaPiana]

@sanders41 I believe I broke this with the fideslib merge. What I think might be happening here is that the root users isn't getting created/seeded, but I'm not sure

[adamsachs]

looks good to me, and i verified that things are working now on nox -s test_env just to be sure. thanks for the updated PR description to explain the changes!