[SQL] az sql mi create, az sql mi update: Add --service-principal-type parameter to support Win Auth (Kerberos)

[ReneaMoso]

Description
Adding Service Principal parameter to az sql mi update and az sql mi create command for Windows Authentication for MI feature.

Testing Guide
A scenario test has been added for update of MI with service principal.
For manual testing: use az sql mi update and az sql mi create with --service-principal-type SystemAssigned

This checklist is used to make sure that common guidelines for a pull request are followed.

• The PR title and description has followed the guideline in Submitting Pull Requests.

• I adhere to the Command Guidelines.

• I adhere to the Error Handling Guidelines.

[yonzhan]

SQL

[evelyn-ys]

It seems not following our guideline for managed identity: https://github.com/Azure/azure-cli/blob/dev/doc/managed_identity_command_guideline.md

Adding @zhoxing-ms for review

[ReneaMoso]

@evelyn-ys It appears that the existing command already doesn't follow the guidelines. I have not added a new command, only added a new parameter to existing command, as per PM's request for this feature. We are not looking to change the command at this time because this feature is supposed to be released soon.

[ReneaMoso]

@evelyn-ys @zhoxing-ms Could someone please review and approve this PR? The snap is in less than a week and I have not heard from anyone in a while?

[evelyn-ys]

LGTM

Since we have not had best practice for --service-principal-type so I'd consider this PR isn't violating our guideline. I prefer to approve this PR @zhoxing-ms

[zhoxing-ms]

In fact, we have only formulated guidelines for managed identity managed_identity_command_guideline but there is no design guidelines for service principal at present. So I personally think it is not necessary to make the service principal parameters refer to the guidelines of managed identity, especially when the identity parameter itself did not follow the guideline of managed identity in sql module.

In addition, I think the service principal also needs to formulate it's own guidelines, if it's usage is similar to managed identity, then it can refer to managed identity guideline. + service principal owner @jiasli please be aware.