az cli missing functionality in az cli - az keyvault certificate pending ....

### Describe the bug

After creating certificate in azure keyvault using below command
`az keyvault certificate create`
There is not option to download the csr for signing using az cli or powershell??
`az keyvault certificate pending ....`

It's only possible to download using the portal at the moment??

### Related command

az keyvault certificate create
az keyvault certificate pending ....
az keyvault certificate pending merge

### Errors

There is no error since the functionality is not available

### Issue script & Debug output

There is no error since the functionality is not available

### Expected behavior

az keyvault certificate pending download

### Environment Summary

{
"azure-cli": "2.55.0",
"azure-cli-core": "2.55.0",
"azure-cli-telemetry": "1.1.0",
"extensions": {
"ssh": "2.0.1"
}
}

### Additional context

Only available to download the csr via portal