[Network] ZoneType is None

[haroldrandom]

Describe the bug
ZoneType is None. So there is a part of help message of az network dns zone create -h missing

To Reproduce
az network dns zone create -h

Command
    az network dns zone create : Create a DNS zone.

Arguments
    --name -n           [Required] : The name of the zone.
    --resource-group -g [Required] : Name of resource group. You can configure the default group
                                     using `az configure --defaults group=<name>`.
    --if-none-match                : Only create a DNS zone if one doesn't exist that matches the
                                     given name.
    --parent-name -p               : Specify if parent zone exists for this zone and delegation for
                                     the child zone in the parent is to be added.
    --tags                         : Space-separated tags in 'key[=value]' format. Use "" to clear
                                     existing tags.
    --zone-type                    : Type of DNS zone to create.  Default: Public. (HERE MISSING)

Private Zone Arguments
    --registration-vnets           : Space-separated names or IDs of virtual networks that register
                                     hostnames in this DNS zone.
    --resolution-vnets             : Space-separated names or IDs of virtual networks that resolve
                                     records in this DNS zone.

Global Arguments
    --debug                        : Increase logging verbosity to show all debug logs.
    --help -h                      : Show this help message and exit.
    --output -o                    : Output format.  Allowed values: json, jsonc, none, table, tsv,
                                     yaml.  Default: json.
    --query                        : JMESPath query string. See http://jmespath.org/ for more
                                     information and examples.
    --subscription                 : Name or ID of subscription. You can configure the default
                                     subscription using `az account set -s NAME_OR_ID`.
    --verbose                      : Increase logging verbosity. Use --debug for full debug logs.

Expected behavior
There is some extra info in "HERE MISSING" above: Allowed values: Public, Private

Environment summary
Not related

Additional context
None

[haroldrandom]

planning on S163