Shield Server API response not returning a proper status code

[mabdh]

Describe the bug There are several improper status code return by shield server API

To Reproduce

• Create user that already exist with POST /admin/v1beta1/users return 500
• Create a project without org_id in its body with POST /admin/v1beta1/projects return 500

Expected behavior API status code should return error properly and not return 500 for every call. e.g.

• If we create user that already exist with POST /admin/v1beta1/users better to return 4xx (409 or 400) instead of returning 500. Or we can make it idempotent.
• If we create a project without org_id in its body with POST /admin/v1beta1/projects, that should return 400. instead of returning 500