Disabled highlighting in writing passages
Disabled highlighting in writing passages

Test Plan:
Check both a reading and a writing passage to see if you can make highlights.

Reviewers: sean, mattdunnrankin

Reviewed By: mattdunnrankin

Subscribers: jared

Differential Revision: https://phabricator.khanacademy.org/D29759

learningequality/perseus,ariabuckles/perseus,learningequality/perseus,ariabuckles/perseus,ariabuckles/perseus,ariabuckles/perseus