Skip file extension on CSR template kind param

The Foreman routes do not allow an extension on the kind, leading to 404
errors.

app/controllers/concerns/foreman_wds/unattended_controller_extensions.rb

 module ForemanWds
   module UnattendedControllerExtensions
     def host_template
-      return wds_render_csr if params[:kind] == 'csr_attributes.yaml'
+      return wds_render_csr if params[:kind] == 'csr_attributes'
       return wds_deploy_localboot if params[:kind] == 'wds_localboot'
       super
     end