feat(stepfunctions-tasks): add configurable timeout

[naaa760]

Title: Configurable timeout for CallAwsServiceCrossRegion Lambda

Issue #

• Closes (stepfunctions_tasks): Setting the timeout on the Lambda function constructed by CallAwsServiceCrossRegion #36823.

Reason for this change :

• 30s Lambda timeout is hardcoded; long-running cross-region calls (e.g. large S3 copy) need a configurable timeout.

Description of changes

• Added optional timeout?: Duration to the task props (default 30s).
• Wired it through to the internal Lambda. No change when not set.
• New or updated permissions
• None.

How you validated

• Unit test: custom timeout (120s) and template check for Lambda Timeout: 120. Existing tests still pass.

Checklist

• Code adheres to CONTRIBUTING GUIDE and DESIGN GUIDELINES.

[aws-cdk-automation]

The pull request linter fails with the following errors:

❌ Features must contain a change to a README file.
❌ Features must contain a change to an integration test file and the resulting snapshot.

If you believe this pull request should receive an exemption, please comment and provide a justification. A comment requesting an exemption should contain the text Exemption Request. Additionally, if clarification is needed, add Clarification Request to a comment.