Allow S3 to retry on HTTP response 200 with InternalError (#3699)

## Motivation and Context
https://github.com/awslabs/aws-sdk-rust/issues/1163

## Description
When the S3 SDK processes a response with the 200 status code but with
`InternalError`, the SDK today does not trigger a retry through any
classifier in the chain: `AwsErrorCodeClassifier`,
`ModeledAsRetryableClassifier`, `HttpStatusCodeClassifier`, and
`TransientErrorClassifier`. To address it, this PR updates
`AwsErrorCodeClassifier` only for S3 so that it classifies
`InternalError` as retryable.

## Testing
- [x] CI
- [x] Added traced test to the existing test file `status-200-errors.rs`

## Checklist
- [x] I have updated `CHANGELOG.next.toml` if I made changes to the AWS
SDK, generated SDK code, or SDK runtime crates

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