Maintenance: Fix ruff lint issues in event_handler module

[leandrodamascena]

Why is this needed?

Fix new ruff lint violations in aws_lambda_powertools/event_handler/ after the target bump.

Mostly Optional[X] to X | None and List[X] to list[X] changes.

Which area does this relate to?

Automation

Solution

No response

Acknowledgment

• This request meets Powertools for AWS Lambda (Python) Tenets
• Should this be considered in other Powertools for AWS Lambda languages? i.e. Java, TypeScript, and .NET