Fix issue where phame "View Live" functionality works by using POST not GET

Summary: Currently you can't refresh the live blog or a blog post after clicking "View Live" due to POST action. I have removed the setRenderAsForm call on the "View Live" actions. I am unsure if this has any unintended consequences but I have tested and not found any.

Test Plan: Click the "View Live" action within a blog post or blog, and observe that the request occurs via GET not POST

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Differential Revision: https://secure.phabricator.com/D6314