[MySQL] Fix flexible server AD admin creation

[Copilot]

Related command

az mysql flexible-server ad-admin create

Description

AD admin creation fails after the MySQL Flexible Server SDK upgrade because plain dictionaries no longer receive SDK REST serialization.

• Use AzureADAdministrator for the request payload.
• Restores nested properties serialization and REST field names:

models.AzureADAdministrator(
    tenant_id=get_tenant_id(),
    identity_resource_id=identity
)

Testing Guide

Run az mysql flexible-server ad-admin create with a user-assigned identity.

History Notes

[MySQL] az mysql flexible-server ad-admin create: Fix AD admin creation

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• 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.

• Fixes Release 2.89.0 breaks creating an AD Admin on a MySQL Flexible Server #33837

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[Copilot]

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[azure-pipelines]

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[azure-client-tools-agent]

Live test skipped

⏭️ Skipping the live test for this revision because no new test file was added (tests/**/test_*.py).

The live-test pipeline runs only the test files a PR changes, so there is nothing to execute for this commit. This is informational — a regression test is encouraged where it makes sense, but not required. If a test file is added in a later commit, the live test will run automatically.

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Posted by agent-assist (autonomous bug-fix pipeline).

[Yong Zhang (yonzhan)]

MySQL

[Aditya Pujara (a0x1ab)]

Copilot please review and implement all unaddressed human feedback through Yong Zhang (@yonzhan)'s latest comment at #33838 (comment), then push the fix to this PR.

Human review feedback to implement:
MySQL

---

Posted by agent-assist (autonomous bug-fix pipeline).

[Copilot]

Copilot please review and implement all unaddressed human feedback through Yong Zhang (@yonzhan)'s latest comment at #33838 (comment), then push the fix to thi...

The referenced human comment contains only “MySQL” and does not specify a requested change. Please provide the concrete feedback to implement.

[Aditya Pujara (a0x1ab)]

Copilot please review and implement all unaddressed human feedback through Yong Zhang (@yonzhan)'s latest comment at #33838 (comment), then push the fix to this PR.

Human review feedback to implement:
MySQL

---

Posted by agent-assist (autonomous bug-fix pipeline).

[Aditya Pujara (a0x1ab)]

Copilot please review and implement all unaddressed human feedback through Yong Zhang (@yonzhan)'s latest comment at #33838 (comment), then push the fix to this PR.

Human review feedback to implement:
MySQL

---

Posted by agent-assist (autonomous bug-fix pipeline).

[azure-client-tools-agent]

Copilot finished without pushing a fix after 3 automated attempts for the feedback at #33838 (comment). Leaving this PR for manual follow-up.

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Posted by agent-assist (autonomous bug-fix pipeline).

[microsoft-github-policy-service]

🔔 Routing this PR to @Azure/act-codegen-extensibility-squad.