Limit what label fields we expose on Projects::LabelsController#index

app/controllers/projects/labels_controller.rb

@@ -18,7 +18,7 @@ class Projects::LabelsController < Projects::ApplicationController
     respond_to do |format|
       format.html
       format.json do
-        render json: @labels
+        render json: @labels.as_json(only: [:id, :title, :color])
       end
     end
   end