S3: Support AWS_S3_US_EAST_1_REGIONAL_ENDPOINT environment variable with AWS SDK for Go v2

[ewbankkit]

Description

Respect a valid value for the AWS_S3_US_EAST_1_REGIONAL_ENDPOINT environment variable when configuring the S3 API client.

Relations

Closes #33872.

[github-actions]

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[github-actions]

This functionality has been released in v5.21.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

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[github-actions]

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