WL-3544 : A announcement is public if it is in a public site or is public

Issue: Annoucements made on .anon site do not appear in public dropdown list
```Site.isPubView()``` is acutally if the site should be included in the public directory of sites, not that the site can be publicly accessed. When you grant access in Site Info -> Manage Access you are adding the .anon role to the site.