Admin can add a new staff member by filtering the list of users

[adamspd]

Feature Description

Currently, an administrator can add a staff member by entering the individual's name and email address, after which an account is created for them. Subsequently, an email is dispatched to the new staff member, prompting them to set a new password.

What happens if the staff member already possesses a user account? To address this potential overlap, it might be beneficial to introduce an option that allows the addition of a staff member by selecting from existing user accounts.