Cleanup audio/video shortcodes in the media modal:

* On the controller's `update`, `replace`, and `close` events, call `detach()` on the frame
* Cleanup the HTML ouput of the Underscore templates.
* Move some logic from the Underscore template to the `VideoDetails` view class.

See #27016.



git-svn-id: https://develop.svn.wordpress.org/trunk@27440 602fd350-edb4-49c9-b593-d223f7449a82