ID 564263 - User Management: A deleted user cannot login if re-added with the same username

Problem summary
If a deleted username is readded, that username won't be able to log into Flix

Customer reported version
flix_7.0.0

Steps to reproduce

1. create a user1
2. delete user1
3. create user1
4. login with user1

Expected behaviour
User1 should be able to log in

Actual behaviour
User1 can not log in. The following error can be found in the server log file:

WARN[82297]auth.HTTPBasicAuthenticator.basicAuth: cannot authenticate deleted user              User="User{user1 Admin user}"

Workaround
Use a different username

Reproduced by support
This bug has been reproduced in:
Flix 7.0.0