feat(lambda): support for customer managed encryption (CMCMK) (#32072)

### Issue # (if applicable)
NA

### Reason for this change

AWS Lambda is adding a new feature that allows customers to use their
own AWS KMS keys to encrypt their Lambda function code stored in Amazon
S3. This gives customers greater control and flexibility over the
encryption of their sensitive data and code. The new SourceKMSKeyArn
field in the Lambda function's Code object enables customers to specify
the ARN of the KMS key to be used for encryption.

### Description of how you validated changes

Have added unit tests and integration test to verify the feature.

### Checklist
- [ ] My code adheres to the [CONTRIBUTING
GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and
[DESIGN
GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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

Author: Vandita2020