admin/settings/opal/polarity should have more limited access

It's not clear to me why this callback exists at all, since there doesn't appear to be anything calling it. It's strange to have an "access content" callback in the admin section, but more than that, it seems like an easy way to crash a site with a DoS attack. Requests to that URL can fire off a second request to api.microsofttranslator.com, wait until that responds, then do a series of database queries. The callback should at least have its own permission so site administrators can decide how open they want to make such a resource-hungry process.