Set `DynamoDBDocumentClientCommand::input` to recursive readonly.

[kuhe]

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

Identified in #7012

Regression Issue

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

SDK version number

latest

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

all

Reproduction Steps

instantiate any Command from lib-dynamodb and modify a sub-property of input.

Observed Behavior

no type error

Expected Behavior

typescript error for modifying a readonly property

Possible Solution

Use a type transform to set DynamoDBDocumentClientCommand::input to a recursively readonly type.

Additional Information/Context

No response