Regional Admin Permissions Assignments

# 🐛 Summary #

The regional admin is able to invite a user and assign them to the global admin or global view role.

## To reproduce ##

Steps to reproduce the behavior:

1. Click 'My Account'
2. 'Manage Users'
3. 'Invite User'

## Expected behavior ##

No roles assignment should be possible. This will only send out invites without creating users in the DB.

Additional note, role assignments in the near term will be managed by ATC directly and not delegated outside the team.

## Any helpful log output or screenshots ##