[ECR] [request]: ETR Of Image Scanning Duration

### Community Note

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**Tell us about your request**

_This request was submitted on behalf of a customer_

An indication of how long it will take to scan selected ECR repositories when using the image scanning feature.

**Which service(s) is this request for?**
ECR

**Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard?**
N/A

**Are you currently working around this issue?**
No

**Additional context**
N/A

**Attachments**
N/A

The issue names ECR image scanning but no repository files, tests, or implementation entry points. Start by reviewing the ECR image-scanning behavior and available status or reporting interfaces; done would require a defined way to indicate how long scanning selected repositories will take.

Written by the indexing model from the issue text.