deploy-all.ps1 failed when non-json output

Fixes #906

k8s/helm/deploy-all.ps1

@@ -28,7 +28,7 @@ if ($externalDns -eq "aks") {
         exit 1
     }
     Write-Host "Getting DNS of AKS of AKS $aksName (in resource group $aksRg)..." -ForegroundColor Green
-    $dns = $(az aks show -n $aksName  -g $aksRg --query addonProfiles.httpApplicationRouting.config.HTTPApplicationRoutingZoneName)
+    $dns = $(az aks show -n $aksName  -g $aksRg --query addonProfiles.httpApplicationRouting.config.HTTPApplicationRoutingZoneName -o json)
     if ([string]::IsNullOrEmpty($dns)) {
         Write-Host "Error getting DNS of AKS $aksName (in resource group $aksRg). Please ensure AKS has httpRouting enabled AND Azure CLI is logged & in version 2.0.37 or higher" -ForegroundColor Red
         exit 1