Add excluded request routes into staging namespace

It makes sense to the routes into the staging namespace.

It was required here:

#6336

Co-authored-by: Moisés Déniz Alemán <mdeniz@suse.com>
Co-authored-by: David Kang <dkang@suse.com>
Co-authored-by: Christian Bruckmayer <cbruckmayer@suse.com>

src/api/config/routes.rb

@@ -736,11 +736,11 @@ def self.public_or_about_path?(request)
       get 'staged_requests' => 'staged_requests#index', constraints: cons
       resource :staged_requests, controller: 'staged_requests', only: [:create, :destroy], constraints: cons
     end
-  end
 
-  controller 'staging/excluded_requests' do
-    post 'staging_excluded_requests/:number/:project_name' => :create, constraints: cons
-    delete 'staging_excluded_requests/:number' => :destroy, constraints: cons
+    controller 'excluded_requests' do
+      post 'staging_excluded_requests/:number/:project_name' => :create, constraints: cons
+      delete 'staging_excluded_requests/:number' => :destroy, constraints: cons
+    end
   end
 
   controller :source_attribute do