Azure VMware Solution: Missing provisioningState enum for Addon resource

[sigmer]

The vmware.json swagger spec for the vmware resource provider seems to have incorrect or incomplete enum values for provisioningState for the Addon resource in the 2020-07-17-preview version.

Immediately after creating a new addon, the provisioningState returned from the api is Building but that is not a valid state according to the spec:

        "provisioningState": {
          "description": "The state of the addon provisioning",
          "type": "string",
          "readOnly": true,
          "enum": [
            "Succeeded",
            "Failed",
            "Cancelled",
            "Deleting",
            "Updating"
          ],
          "x-ms-enum": {
            "name": "AddonProvisioningState",
            "modelAsString": true
          }
        }

cc @ctaggart

[ctaggart]

I added it to the 2021-01-01-preview API in #12762.