chore(step-function-tasks): add comment that aws-sdk integration pattern is not impacted by sdk upgrade (#29795)

### Reason for this change

For upgrading sdkv2 to sdkv3, I have confirmed that the [pattern](https://docs.aws.amazon.com/step-functions/latest/dg/supported-services-awssdk.html) used by step function task is not impacted by the migration and will remain the same. 

Adding a comment to add historical context for anyone revisiting this package for another sdk upgrade.

### Description of changes

Just added comments. No code changes.

### Description of how you validated changes

No tests added for comments

### 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)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: vinayak-kukreja

packages/aws-cdk-lib/aws-stepfunctions-tasks/lib/aws-sdk/call-aws-service.ts

@@ -118,6 +118,9 @@ export class CallAwsService extends sfn.TaskStateBase {
       service = service.toLowerCase();
     }
 
+    // The pattern here is: "arn:aws:states:::aws-sdk:serviceName:apiAction.[serviceIntegrationPattern]"
+    // See here: https://docs.aws.amazon.com/step-functions/latest/dg/supported-services-awssdk.html
+    // This does not change with sdk upgrades, TT:P125388388
     return {
       Resource: integrationResourceArn(
         'aws-sdk',