Only specific email domains restriction makes no sense with no email domain provided

Issue Summary

The Enterprise Workspace restrictions - membership restriction has an option `Only specific email domains`, while it's possible to apply this setting w/o providing any specific domain, which lead to the next state: * Anyone with any email domain can be added to this Workspace.

Steps to Reproduce

1. Create an Enterprise
2. Go to the Enterprise Dashboard => Workspace & board permissions => Workspace membership restrictions
3. Set the `Only specific email domains option` w/o providing any domain

Expected Results

The UX would be better, if the pref updates when the user clicks the Add  button and is successful, instead of updating when clicking Only specific email domains .

Actual Results

Restriction is set technically, but it still do nothing and allows user with any domain to become an Enterprise member

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available

Notes

1. The same applied for the `Managed members or specific email domains` option in case Enterprise has domain / users claimed
2. The same applied for the Premium Workspace membership restriction setting.