VE-1728: Not necessary to resize image client-side

Originally this ticket was to import the latest version of Vignette-js and remove this now-unnecessary code. However, @kvas-damian recently updated Vignette-js and it includes the change we need. This pull request now only removes the unnecessary code.

Changes were not made to WikiaMediaPageWidget as it is still using the old thumbnailer and will soon be removed with the new media tool.