The email address of the user to remove from the group.
Group Names
A comma-separated list of the user groups, product profile names or an administrative groups. For an admin group, the name can be one of the fixed groups _org_admin, _deployment_admin, or _support_admin; or a group-specific admin group. These are identified with a prefix on the group name _admin_groupName , _product_admin_productName, _developer_groupName. If the group exists but the admin group does not, an empty list is returned.
