azurerm_mssql_managed_instance fix identity bug and updating subnet_id

[wyattfry]

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Description

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Change Log

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• azurerm_resource - support for the thing1 property [GH-00000]

This is a (please select all that apply):

• Bug Fix
• New Feature (ie adding a service, resource, or data source)
• Enhancement
• Breaking Change

Related Issue(s)

Fixes #0000

Note

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[wyattfry]

This the crux of the identity bug fix, SystemOrUserAssignedIdentityOptional is XOR, exclusive or. SystemAssignedUserAssignedIdentityOption is true OR, i.e. one, the other, or both.

[wyattfry]

1 failing acceptance test, due to timeout, rerunning that one test

        API Response:
        ----[start]----
        {"name":"31930286-4dff-48ff-a098-15853e0712d0","status":"Failed","startTime":"2024-12-20T17:23:44.937Z","error":{"code":"ConflictingServerOperation","message":"Server
        'acctestsqlserver241220165729791029' is busy with another operation. Please
        try your operation later."}}
        -----[end]-----
--- FAIL: TestAccMsSqlManagedInstance_identity (4482.45s)