DEV: enable cors to all cdn get requests from workbox. (#10685)

Now all external requests from the service worker will be in CORS mode without credentials.

app/controllers/svg_sprite_controller.rb

@@ -3,6 +3,8 @@
 class SvgSpriteController < ApplicationController
   skip_before_action :preload_json, :redirect_to_login_if_required, :check_xhr, :verify_authenticity_token, only: [:show, :search, :svg_icon]
 
+  cdn_action only: [:show, :search, :svg_icon]
+
   requires_login except: [:show, :svg_icon]
 
   def show