Currently, a user can bypass the domain allowlist
by creating an account with an email that is on the list,
then changing their email to a domain that is not
on the list.

Changelog: fixed

Fix conditional order

Remove accidental changes

Fix failing specs

Remove bad spec

Allow admin to add user not on allowlist

Validate if not new record

Remove unnecessary spec changes

Validate domain update

Use existing methods in restricted signup concern
to validate domain update

Add specs for deny and restricted

Add specs for updating domain
to denied or restricted domain

Undo unintentional changes

Remove unneeded spec

Fix bad spec

Reuse signup restrictions method

Change method name back

Was breaking other specs

Check if not new record