{Role} az ad sp create-for-rbac: Add usage link to --sdk-auth's help message

[jiasli]

Description

az ad sp create-for-rbac: Add usage link to --sdk-auth's help message

Reference email: Deprecate generating JSON auth file in Azure CLI

Testing Guide

> az ad sp create-for-rbac --help

    --sdk-auth         : Generate a JSON dictionary compatible with Azure SDK. For how to use it
                         with Azure SDK, see https://aka.ms/azsdk/python/azidmigration.  Allowed
                         values: false, true.

[jiasli]

Adjust the order of warnings. Show credential warning first.

Before:

> az ad sp create-for-rbac --sdk-auth
In a future release, this command will NOT create a 'Contributor' role assignment by default. If needed, use the --role argument to explicitly create a role assignment.
Creating 'Contributor' role assignment under scope '/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590'
  Retrying role assignment creation: 1/36
The output includes credentials that you must protect. Be sure that you do not include these credentials in your code or check the credentials into your source control. For more information, see https://aka.ms/azadsp-cli
{
  ...
}

After:

> az ad sp create-for-rbac --sdk-auth
The output includes credentials that you must protect. Be sure that you do not include these credentials in your code or check the credentials into your source control. For more information, see https://aka.ms/azadsp-cli
In a future release, this command will NOT create a 'Contributor' role assignment by default. If needed, use the --role argument to explicitly create a role assignment.
Creating 'Contributor' role assignment under scope '/subscriptions/0b1f6471-1bf0-4dda-aec3-cb9272f09590'
  Retrying role assignment creation: 1/36
{
  ...
}

[yonzhan]

Role

[lmazuel]

Still misleading to me, since it's not compatible with SDK as a whole. I would be more explicit.

"SDK has deprecated usage of authentication file. More details here: aka"