Use person number as username when employee has no email

Summary:

Use person number as username when employee has no email

Content (please ensure you mask any confidential information):

Currently, the username is generated using the employee’s email address.
If an employee doesn’t have an email, the system defaults to using first name.last name as the username.

I would like to modify this behavior so that when no email is available, the person number is used as the username instead.

Would this approach be applicable?

Version (include the version you are using, if applicable):

Currently, the username is generated using the employee’s email address.
If an employee doesn’t have an email, the system defaults to using