Merge branch 'issue_3946' into 'master'

Improve UI consistency for admin area

Closes #3946

See merge request !4424

spec/controllers/admin/projects_controller_spec.rb

@@ -11,12 +11,12 @@ describe Admin::ProjectsController do
     render_views
     it 'retrieves the project for the given visibility level' do
-      get :index, visibility_levels: [Gitlab::VisibilityLevel::PUBLIC]
+      get :index, visibility_level: [Gitlab::VisibilityLevel::PUBLIC]
       expect(response.body).to match(project.name)
     end
     it 'does not retrieve the project' do
-      get :index, visibility_levels: [Gitlab::VisibilityLevel::INTERNAL]
+      get :index, visibility_level: [Gitlab::VisibilityLevel::INTERNAL]
       expect(response.body).not_to match(project.name)
     end
   end