Allow to pass overrideConfiguration per request

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### Problem:

If i want to pass additional headers with Decrypt call (e.g Confused Deputy protection). I need to provide for each account own KmsClient. Instead in SdkV2 i can call .overrideConfiguration on request (you already use it for API_NAMESPACE).

If it will be possible to add .overrideConfiguration per call encrypt/decrypt i can use the same KmsClient for all accounts.

### Solution:

A description of the possible solution in terms of Encryption SDK architecture.

I see 2 options:
1. in AwsCrypto.decryptData/ecryptData provide additional argument with options
2. When construct KmsMasterKeyProvider ask for supplier for override. But there we need to send something in addition to identify context of request

### Out of scope:

Is there anything the solution will intentionally NOT address?

[//]: # (NOTE: If you believe this might be a security issue, please email aws-security@amazon.com instead of creating a GitHub issue. For more details, see the AWS Vulnerability Reporting Guide: https://aws.amazon.com/security/vulnerability-reporting/ )

まず AwsCrypto.decryptData/encryptData と KmsMasterKeyProvider を追跡し、リクエストごとの AWS SDK v2 overrideConfiguration をどこに組み込めるかを理解します。既存の API_NAMESPACE の使用方法を 2 つの提案されたオプションと比較し、そのうえで encrypt と decrypt に必要なリクエストコンテキストと API の形を定義します。完了の条件は、1 つの KmsClient で複数のアカウントからのリクエストを処理でき、追加のヘッダーが KMS 呼び出しに到達することです。

索引モデルが issue の本文から書いたものです。