commenting out invalid redirect target so that build can succeed

Author: 45930

docusaurus.config.js

@@ -286,10 +286,6 @@ module.exports = {
             from: '/mesa-upgrade/appendix',
             to: '/network-upgrades/mesa/appendix',
           },
-          {
-            from: '/mesa-upgrade/validation',
-            to: '/network-upgrades/mesa/validation',
-          },
           {
             from: '/mesa-upgrade/upgrade-steps/pre-upgrade',
             to: '/network-upgrades/mesa/upgrade-steps/pre-upgrade',