Mob 241 - Fatal Error calling DataMartService::getTopWikisByPageviews()

Fix for: https://wikia-inc.atlassian.net/browse/MOB-241

Added support for multiple languages to ArticlesApi->getTopByHub() and wrapped with array language string on RandomWikiHelper befor call to DataMartService::getTopWikisByPageviews.

I didn't found any other calls of DataMartService::getTopWikisByPageviews that use language parameter that was now changed to array.

@federico-lox @macbre