Open up all hints immediately on the translate preview page.

Summary:
When on translate.ka.org, our translators have complained it
would be easier for them if they didn't have to click to get
all the hints.  So we do it for them.

Test Plan:
Go to: http://translate.khanacademy.dev/preview/content/items?exercises=functions_1&mp-r-id=uKsNwZs=#x1c985273

See that all hints open up as you click between the different assessment items.

Reviewers: alpert

Reviewed By: alpert

Differential Revision: http://phabricator.khanacademy.org/D9691