Setting SQL Server AD AD Admin is not possible when omitting the displayname parameter

According to the documentation, the `displayName` parameter of the `az sql server ad-admin create` is optional:


However, when I execute this command:

```azcli
az sql server ad-admin create --server --resource-group --object-id
```
I'm presented with this error:

```
##[error]ERROR: (InvalidResourceIdSegment) The 'parameters.properties' segment in the url is invalid.
```

When I add the display-name parameter to that command, the command runs and finishes successfully.

I think the documentation must be changed and it must be stated that both the `--object-id` and `--display-name` parameters are mandatory.

---
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* ID: 0bca10a0-5310-1ed6-8391-57a8ccafb27f
* Version Independent ID: 4144f2fa-35f1-533c-e48b-17180f03203e
* Content: [az sql server ad-admin](https://docs.microsoft.com/en-us/cli/azure/sql/server/ad-admin?view=azure-cli-latest)
* Content Source: [latest/docs-ref-autogen/sql/server/ad-admin.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/main/latest/docs-ref-autogen/sql/server/ad-admin.yml)
* Service: **sql-database**
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**