Empty video blocks throw ActionView::Template::Error on show

[anarchivist]

Submitted as EXHBTF-1259

See, for instance: https://app.honeybadger.io/projects/49092/faults/68022762

Users can't see the feature page, as it throws the error and redirects to the status page. User remediation is to remove the empty block, but perhaps we can handle this more cleanly?

[mejackreed]

Tracking upstream here: madebymany/sir-trevor-rails#39