OZG-4320 OZG-4488 Revert to NodeJS 16 for builds at Jenkins

`mvn` not found in NodeJS 18 image - need to investigate later.

Jenkinsfile

 pipeline {
     agent {
         node {
-            label 'jenkins-build-agent-nodejs-18'
+            label 'jenkins-build-agent-nodejs-16'
         }
     }