Added support for RequestPayer property in TransferUtility BaseDownloadRequest class.

[ashishdhingra]

Description

Added support for RequestPayer property in TransferUtility BaseDownloadRequest class.

Motivation and Context

Fixes #3301

Testing

Tested locally by setting cross account access (refer https://repost.aws/knowledge-center/cross-account-access-s3) and enabling Request Payer in the bucket. Used Visual Studio debug session to first replicate the issue and then validate the fix using code below:

try
{
    IAmazonS3 s3Client = new AmazonS3Client("<<access-key-id>>", "<<secret-id>>", <<bucket-regionendpoint>>);
    var transferUtil = new TransferUtility(s3Client);
    await transferUtil.DownloadAsync(new TransferUtilityDownloadRequest
    {
        BucketName = "<<bucket-name>>",
        Key = "<<key-name>>",
        FilePath = @"<<absolute-file-path>>",
        RequestPayer = RequestPayer.Requester
    });
}
catch (Exception ex)
{
    await Console.Out.WriteLineAsync(ex.Message);
    throw;
}

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have read the README document
• I have added tests to cover my changes
• All new and existing tests passed

License

• I confirm that this pull request can be released under the Apache 2 license