DEV: Fix theme qunit error messages (#14420)

DEV: Fix theme qunit error messages (#14420)

diff --git a/app/controllers/qunit_controller.rb b/app/controllers/qunit_controller.rb
index 26a1160..309d2af 100644
--- a/app/controllers/qunit_controller.rb
+++ b/app/controllers/qunit_controller.rb
@@ -31,7 +31,7 @@ class QunitController < ApplicationController
     end
 
     if param_key && theme.blank?
-      return render plain: "Can't find theme with #{param_key} #{params[param_key].inspect}", status: :not_found
+      return render plain: "Can't find theme with #{param_key} #{get_param(param_key).inspect}", status: :not_found
     end
 
     if !param_key

GitHub sha: db69b8718765ff386ccae7e5b7db42ee21f2dc30

This commit appears in #14420 which was approved by eviltrout. It was merged by CvX.