### Elasticsearch Version

8.3.1

### Installed Plugins

_No response_

### Java Version

_bundled_

### OS Version

Linux 5.4.196-108.356.amzn2.x86_64

### Problem Description

Elasticsearch in EKS does not honour `eks.amazonaws.com/sts-regional-endpoints=true` for IAM access with AWS regions. It always sends it's API calls to `us-east-1`.

### Steps to Reproduce

Deploy Elasticsearch in EKS using operator with the following env
```
          containers:
            - env:
                - name: AWS_ROLE_SESSION_NAME
                  value: snapshot-repo
                - name: ZONE
                  valueFrom:
                    fieldRef:
                      fieldPath: metadata.annotations['topology.kubernetes.io/zone']
```

Create service account with the annotations
```
  annotations:
    eks.amazonaws.com/role-arn: redacted
    eks.amazonaws.com/sts-regional-endpoints: "true"
```

Create snapshot repo
```
PUT _snapshot/s3backup
{
    "type": "s3",
    "settings": {
      "bucket": "redacted",
      "server_side_encryption": "true",
      "max_restore_bytes_per_sec": "500mb",
      "storage_class": "intelligent_tiering",
      "use_throttle_retries": "true",
      "readonly": "false",
      "base_path": "snapshot",
      "region": "us-west-2",
      "max_snapshot_bytes_per_sec": "500mb",
      "endpoint": "s3.us-west-2.amazonaws.com"
  }
}
```

Run snapshot

View cloudtrail events for service account name
![2022-08-08_11-36-48](https://user-images.githubusercontent.com/64858237/183456721-db86153c-ccc3-4821-8c84-f8c85cb4e495.png)


### Logs (if relevant)

_No response_
modules/repository-s3/src/main/java/org/elasticsearch/repositories/s3/S3Service.java
/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the Elastic License
 * 2.0 and the Server Side Public License, v 1; you may not use this file except
 * in compliance with, at your election, the Elastic License 2.0 or the Server
 * Side Public License, v 1.
 */
package org.elasticsearch.repositories.s3;
import com.amazonaws.ClientConfiguration;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSCredentialsProvider;
import com.amazonaws.auth.AWSCredentialsProviderChain;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.AnonymousAWSCredentials;
import com.amazonaws.auth.EC2ContainerCredentialsProviderWrapper;
import com.amazonaws.auth.STSAssumeRoleWithWebIdentitySessionCredentialsProvider;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.http.IdleConnectionReaper;