fix(stepfunctions-task): elasticloadbalancingv2 service policy (#32419)

### Issue # (if applicable)

Closes #32417.

### Reason for this change

The Step Function actions for `elasticloadbalancingv2` require IAM policies from the `elasticloadbalancing` service, which was missing from the list of exceptions

### Description of changes

Added `elasticloadbalancingv2` to the existing `iamServiceMap` exception table.
I've also sorted said service map alphabetically, which was previously a mix of chronological and alphabetical sorting (see [blame](https://github.com/aws/aws-cdk/blame/2607eb3a905f735b96713dda4f32d28d10d686fd/packages/aws-cdk-lib/aws-stepfunctions-tasks/lib/aws-sdk/call-aws-service.ts#L93-L97)). The only actual change to the list was the addition of `elasticloadbalancingv2`

### Description of how you validated changes

Added both unit and integ test

### Checklist
- [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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