Disable upload CTA when $wgMFEnablePhotoUploadCTA is false

This hides the add an image to this article button when a user
is not logged in. Hopefully it will reduce the volume of bad uploads

Change-Id: Iba385d98874315788a8fc7393a46a465b89e344c
Merge "Disable upload CTA when $wgMFEnablePhotoUploadCTA is false"