Hide wiki activity filter behind FF

app/views/shared/_event_filter.html.haml

@@ -15,6 +15,6 @@
       = render_if_exists 'events/epics_filter'
     - if comments_visible?
       = event_filter_link EventFilter::COMMENTS, _('Comments'), s_('EventFilterBy|Filter by comments')
-    - if @project.nil? || @project.has_wiki?
+    - if Feature.enabled?(:wiki_events) && (@project.nil? || @project.has_wiki?)
       = event_filter_link EventFilter::WIKI, _('Wiki'), s_('EventFilterBy|Filter by wiki')
     = event_filter_link EventFilter::TEAM, _('Team'), s_('EventFilterBy|Filter by team')