Prevent AttributeError from being raised when lambda event is a list

[e-pavlica]

Description

When an AWS Lambda is invoked via Step Functions, the event given to the handler may be a list instead of a dict if preceded by a Map state. Currently this causes an AttributeError to be raised in the OTEL instrumentation.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

How Has This Been Tested?

• Tested via a Step Function + Lambda
• Added a basic test for this case

Does This PR Require a Core Repo Change?

• Yes. - Link to PR:
• No.

Checklist:

See contributing.md for styleguide, changelog guidelines, and more.

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation has been updated

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: xicreative / name: Evan Pavlica (642a653)