[ECR] [Feature Request]: Support Enhanced scanning in af-south-1,ap-southeast-3 and ap-northeast-3 regions

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**Tell us about your request**
Enable enhanced scanning support in af-south-1,ap-southeast-3 and ap-northeast-3 regions

**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?**
What outcome are you trying to achieve, ultimately, and why is it hard/impossible to do right now? What is the impact of not having this problem solved? The more details you can provide, the better we'll be able to understand and solve the problem.

From the documentation : https://docs.aws.amazon.com/AmazonECR/latest/userguide/image-scanning-enhanced.html#image-scanning-enhanced-considerations
Enhanced scanning isn't supported in the following Regions:
Asia Pacific (Osaka) (ap-northeast-3)
Asia Pacific (Jakarta) (ap-southeast-3)
Africa (Cape Town) (af-south-1)

Enhanced scanning is not supported in certain regions. There is also no scanning tab (option) available on the ECR console for these regions.Because of this we are also losing scan on push option for all repositories even for Basic scanning.I know that we have basic scan supported in these regions. We would like to get the enhanced scanning support in these regions so that we could use inspector to scan the repositories for vulnerabilities in the mentioned regions.