AWS::IAM::User (support drift detection)

### Name of the resource

AWS::IAM::User

### Resource name

_No response_

### Description

Scope of request: I would like CloudFormation to support drift detection on resources of type AWS::IAM::User.

Expected behavior: When checking drift on resources of this type, CloudFormation should report a drift if any of the resources' properties change.

### Other Details

_No response_

The issue names AWS::IAM::User but no file, test, or implementation entry point. Start by reviewing the repository's coverage-roadmap context and define done as reporting drift whenever any property of this resource changes; the implementation and validation locations still need to be identified.

Written by the indexing model from the issue text.