Protocol test `RestJsonHttpPayloadWithStructureAndEmptyResponseBody:Response` failing in smithyVersion=1.59.0

[trivikr]

Checkboxes for prior research

• I've gone through Developer Guide and API reference
• I've checked AWS Forums and StackOverflow.
• I've searched for previous similar issues and didn't find any solution.

Describe the bug

Issue is for team tracking

Regression Issue

• Select this option if this issue appears to be a regression.

SDK version number

N/A

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

All

Reproduction Steps

Enable tests skipped in #7161, and run protocol tests

Observed Behavior

Protocol test RestJsonHttpPayloadWithStructureAndEmptyResponseBody:Response fails

Expected Behavior

Protocol test RestJsonHttpPayloadWithStructureAndEmptyResponseBody:Response should succeed.

Possible Solution

For non-schemas, the null needs to be explicitly populated in https://github.com/aws/aws-sdk-js-v3/blob/main/private/aws-protocoltests-restjson/src/protocols/Aws_restJson1.ts#L3048

For schemas, the fix is likely in output schema ref https://github.com/aws/aws-sdk-js-v3/blob/main/private/aws-protocoltests-restjson-schema/src/schemas/schemas.ts#L977

Additional Information/Context

Protocol test was added in smithy-lang/smithy#2641