Better checking of namespace

We're aiming to get this into release-238 for release tomorrow. This PR is to dev, which will then be cherry-picked into the release branch.

https://wikia-inc.atlassian.net/browse/VE-1397
Checking for '[contenteditable="true"]' is specific to VE - would be good to comment inline on that. However, if that direct connection to VE is already created I would suggest being more explicit about checking if VE is enabled - checking for $('html').hasClass('ve-activated') for instance.