auditmanager: Use v2 AWS SDK

[jar-b]

Description

Switches the auditmanager client to the v2 AWS Go SDK.

Note: No Audit Manager resources have been implemented yet.

Relations

Relates #17981
Relates #18071

[github-actions]

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[github-actions]

This functionality has been released in v4.40.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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