Migrate S3 clients to AWS SDK Go V2

[mye956]

Summary

This PR will migrate the S3 clients implementations and corresponding code paths from AWS SDK Go V1 to AWS SDK Go V2.

Implementation details

• Now using LoadDefaultConfig fromNewConfig as part of V2 migration (ref) in createAWSConfig()
• Now using s3.NewFromConfig() to create the S3 client
• Now using NewDownloader from NewDownloaderWithClient for S3ManagerClient
• Updated S3ManagerClient to now use Download(ctx context.Context, w io.WriterAt, input *s3.GetObjectInput, options ...func(*s3manager.Downloader)) from DownloadWithContext()
• Updated the function parameters for GetObject() of S3Client interface
• aws.*Value to aws.To* updates
• Couple of other replacements of aws-sdk-go/* to aws-sdk-go-v2/*

Testing

Launched a task on a FIPs-enabled host in us-west-2

level=debug time=2025-04-23T20:12:01Z msg="FIPS mode detected, using virtual-host–style URLs for bucket location"
SDK 2025/04/23 20:12:01 DEBUG Request
level=debug time=2025-04-23T20:12:01Z msg="FIPS mode detected, using FIPS-compliant S3 endpoint in supported regions"

Environment variables within the container

/ # echo $TEST1
ABC
/ # echo $TEST2
XYZ

Launched a task on a FIPs-enabled host in a non-supported region ()

level=info time=2025-04-23T20:36:51Z msg="FIPS mode detected on the host"
level=debug time=2025-04-23T20:37:19Z msg="FIPS mode detected, using virtual-host–style URLs for bucket location"

Environment variables within the container

/ # echo $TEST1
ABC
/ # echo $TEST2
XYZ

Tested using dualstack subnet and confirmed the behavior remained the same

Host: blah-agent-test-files-us-west-2-prod.s3.dualstack.us-west-2.amazonaws.com

New tests cover the changes: yes

Description for the changelog

Enhancement - Migrate S3 clients to AWS SDK Go V2

Additional Information

Does this PR include breaking model changes? If so, Have you added transformation functions?

Does this PR include the addition of new environment variables in the README?

Licensing

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.