Admin: Add warning message if no default roles are copied when creating a new customer.

Within the Admin tool, you can create a new company. There are no roles copied/defined by default when creating a new company. Standard practice is to select roles to copy from a drop-down list. However, if this step is omitted by accident, any users associated with that company will not be able to log in and it's not obvious why.

The request is to add a warning message if no roles are selected when creating a new customer in Admin to reduce errors if none are selected.