Non-www redirect to www not working for main domain

### Before opening, please confirm:

- [X] I have checked the [custom domains troubleshooting guide](https://docs.aws.amazon.com/amplify/latest/userguide/custom-domain-troubleshoot-guide.html).
- [X] I have read the guide for [submitting bug reports](https://github.com/aws-amplify/amplify-hosting/blob/master/CONTRIBUTING.md).
- [X] I have done my best to include a minimal, self-contained set of instructions for consistently reproducing the issue.

### App Id

djkqpxwstmtk8

### Region

ap-south-1

### Step

www redirect from non-www

### Status

HTTP Status: 404 (not found)

### Issue or question

Non-www URLs keeps going to an HTTP Status: 404 (not found) page, when a sub-domain is configured it works fine, however does not work with the base domain.

### Error message

HTTP Status: 404 (not found)

### Additional information

The issue names no repository files, tests, or code entry points. Start by reproducing the non-www request for the reported app in ap-south-1 and compare it with the working subdomain behavior; done means the base domain redirects successfully to www instead of returning HTTP 404.

Written by the indexing model from the issue text.