Adding Identity to VirtualMachineScaleSetVM (#18295)

* init

* PR comment

Author: kamusta-msft

specification/compute/resource-manager/Microsoft.Compute/stable/2022-03-01/ComputeRP/virtualMachineScaleSet.json

@@ -5398,6 +5398,10 @@
             "type": "string"
           },
           "description": "The virtual machine zones."
+        },
+        "identity": {
+          "$ref": "./virtualMachine.json#/definitions/VirtualMachineIdentity",
+          "description": "The identity of the virtual machine, if configured."
         }
       },
       "allOf": [