Information on requesting an EV certificate is lacking

There are multiple references on this page to using the `az keyvault certificate get-default-policy` (including with the `--scaffold` option) to create a certificate request, however the certificate policy sections are extremely light on details. Although it redirects to https://docs.microsoft.com/en-us/azure/key-vault/certificates/about-certificates#certificate-policy, that page also does not contain information on how to request an EV certificate.

Digging deep into the API reveals this: https://docs.microsoft.com/en-us/rest/api/keyvault/certificates/get-certificate-policy/get-certificate-policy#issuerparameters, specifically that there is a `cty` parameter inside the `issuerParameters` block returned by the API which we can assume maps to the `certificateType` block in the response from `az keyvault certificate get-default-policy --scaffold`:

```json
{
"issuerParameters": {
"certificateTransparency": null,
"certificateType": "(optional) DigiCert, GlobalSign or WoSign",
"name": "Unknown, Self, or {IssuerName}"
},
"keyProperties": {
"curve": null,
"exportable": true,
"keySize": 2048,
"keyType": "(optional) RSA or RSA-HSM (default RSA)",
"reuseKey": true
},
"lifetimeActions": [
{
"action": {
"actionType": "AutoRenew"
},
"trigger": {
"daysBeforeExpiry": 90,
"lifetimePercentage": null
}
}
],
"secretProperties": {
"contentType": "application/x-pkcs12 or application/x-pem-file"
},
"x509CertificateProperties": {
"ekus": [
"1.3.6.1.5.5.7.3.1"
],
"keyUsage": [
"cRLSign",
"dataEncipherment",
"digitalSignature",
"keyEncipherment",
"keyAgreement",
"keyCertSign"
],
"subject": "C=US, ST=WA, L=Redmond, O=Contoso, OU=Contoso HR, CN=www.contoso.com",
"subjectAlternativeNames": {
"dnsNames": [
"hr.contoso.com",
"m.contoso.com"
],
"emails": [
"hello@contoso.com"
],
"upns": []
},
"validityInMonths": 24
}
}
```

That reply would also seem to indicate that, unlike what is expected by the API, the response from `az keyvault certificate get-default-policy --scaffold` for `certificateType` is actually also incorrect, and should be more like `(optional) OV-SSL or EV-SSL`.

I will also be submitting a request to the documentation team for https://docs.microsoft.com/en-us/azure/key-vault/certificates/about-certificates#certificate-policy (which I will link to this request when completed) to update their documents to make it clearer on how to request an EV SSL certificate.

---
#### Document Details

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* ID: a9c661d7-bf43-5354-015e-3859f30a42a2
* Version Independent ID: fa69e552-5904-ce97-d02c-915c819bdde1
* Content: [az keyvault certificate](https://docs.microsoft.com/en-us/cli/azure/keyvault/certificate?view=azure-cli-latest#az-keyvault-certificate-get-default-policy)
* Content Source: [latest/docs-ref-autogen/keyvault/certificate.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/main/latest/docs-ref-autogen/keyvault/certificate.yml)
* Service: **key-vault**
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**