Added terraform support to configure SMT in SQL Server instances

[modular-magician]

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sql: added `advanced_machine_features` field in `google_sql_database_instance`

Derived from GoogleCloudPlatform/magic-modules#7881

[pdewilde]

#14813

This gets formatted so that all options below this appear to be within the advanced_machine_features subblock

https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/sql_database_instance#threads_per_core

Putting them above this subblock should fix the issue

[github-actions]

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