When rendering for models and views for actions were split up, we began

rendering the model JavaScript for every action on every page,

regardless of apply_to. This caused some actions to fail to

instantiate on pages they weren't supposed to be on.
This change restores a should_render() call for model JavaScript,

ensuring we only get the actions appropriate for the page.

Unit tests pass.
Verified that JavaScript unit tests were no longer erroring out with

actions that couldn't instantiate.