[Sprint/Zero](bug) Allowing users to turn back on boosts (plus) #433.

It seems that the issue was that the boost-rotator was being disabled when a user was signed up to plus, and had hid their boosts. Some users of course want to re-enable those boosts.

I expected that I would have to change the below file too, but did not as it was still working on my test env with it in - that being said on the chance this change not work on the live site: src/app/modules/channels/feed/feed.html