fix(lambda-nodejs): remove smithy models from bundling for AWS SDK v3 runtimes (under feature flag)

[GavinZZ]

Issue # (if applicable)

Closes #31610

Reason for this change

for Node 18+ runtimes, since AWS Lambda includes AWS SDK v3 by default, and CDK excludes all the @aws-sdk/* packages because they’re expected to already be present. However, the CDK currently removes only the @aws-sdk/* packages when bundling for Node 18+ runtimes, but it does not remove the @smithy/* packages. This can cause a mismatch in versions between the @smithy/* packages and the AWS SDK packages that AWS Lambda provides.

The mismatch can happen in the following scenarios. This is a pretty edge case but customers did encounter this issue.

/user-app/node_modules/
  - /@smithy/* (v123) <-- this gets used because it wasn't deleted
  - /@aws-sdk/*  (v123) <-- CDK removes `@aws-sdk/*` currently
/lambda-hidden-folder/node_modules
  - /@smithy/* (v456)
  - /@aws-sdk/* (v456) <-- this gets used as fallback since the module is removed from node_modules by CDK

Description of changes

Add a feature flag. When feature flag is set to true, we will also remove smithy models.

Description of how you validated changes

Added unit tests and integration tests.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

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

[xazhao]

The code LGTM. Just curious what will customers see when there's version mismatch?

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

[GavinZZ]

The code LGTM. Just curious what will customers see when there's version mismatch?

One quick example I can think of if there's a mismatch in version and customer used a newer method in a newer @aws-sdk/* library but with an older @smithy/* library would be TypeError: mySdk.someNewMethod is not a function

[aws-cdk-automation]

AWS CodeBuild CI Report

• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: 7428f07
• Result: SUCCEEDED
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[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).

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