This is a filter on the array provided by a support document. If a value in the array isn't a proper origin, it gets dumped.

So, `{ realm: ['foo.com', 'http://bar.com', 'baz'] }` becomes `{ realm: ['http://bar.com'] }`. Our client side doesn't care if there's errors or if it's malformed, simply if the declared realm is in the support document.