(ecs): create unit tests for drain hook lambda handler

[colifran]

Describe the feature

We need to improve testing coverage of our Lambda handlers. The Lambda handler for drain hooks does not have corresponding unit tests. Unit tests should be created specifically for this handler.

Use Case

Unit tests for the drain hook Lambda handler would improve test coverage and help us find bugs and prevent breaking changes.

Proposed Solution

No response

Other Information

No response

Acknowledgements

• I may be able to implement this feature request
• This feature might incur a breaking change

CDK version used

2.103.1

Environment details (OS name and version, etc.)

MacOS

[msambol]

I'll take this.