ci(toolVersions): set kubectl and helm version from github environment variable (#6471)

Author: ScottMillard

.github/workflows/nonprod-releases.yml

@@ -38,8 +38,8 @@ jobs:
 
       - uses: alexellis/arkade-get@master # https://github.com/alexellis/arkade-get?tab=readme-ov-file#why-do-we-use-use-master
         with:
-          kubectl: v1.33.3
-          helm: latest
+          kubectl: ${{ vars.KUBECTL_VERSION }}
+          helm: ${{ vars.HELM_VERSION }}
 
       - name: Update kubeconfig
         run: |