Maintenance: Resolve Ty diagnostics for utilities/data_classes

[ConnorKirk]

Why is this needed?

This is a sub-issue of #7902.

The utilities/data_classes/ module has 14 ty diagnostics that need to be resolved to expand type checking coverage.

Which area does this relate to?

• Static typing
• Event Source Data Classes

Solution

Resolve all 14 ty diagnostics in utilities/data_classes/ and remove from ty exclusion list in pyproject.toml.

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