added principaltype back (#498)

docs/reference/wingtip/armTemplates/auxiliary/azOpsArm.json

@@ -108,7 +108,7 @@
                 "[resourceId('Microsoft.ManagedIdentity/userAssignedIdentities', variables('userManagedIdentityName'))]"
             ],
             "properties": {
-                //"principalType": "ServicePrincipal",
+                "principalType": "ServicePrincipal",
                 "principalId": "[reference(variables('userManagedIdentityName'), '2018-11-30').principalId]",
                 "roleDefinitionId": "[variables('keyVaultAdminRbac')]"
             }