feat(instrumentation-aws-sdk): Add semconv attributes for AWS Step Functions

This PR adds the aws.step_functions.activity.arn and aws.step_functions.state_machine.arn semantic convention attributes for the following AWS resources:

AWS Step Functions SDK

The ARNs are extracted from request objects, and this behavior is covered by unit tests.

Tests Run:
npm run compile
npm run lint
npm run test

All newly added tests pass, and no regressions were found.

Backward Compatibility:
This change is fully backward compatible. It introduces instrumentation for an additional AWS resource without modifying existing behavior in the auto-instrumentation library.

Author: lukeina2z