[AWS::ECS::AccountSetting] - [Coverage] - Missing CloudFormation support

### Name of the resource

Other

### Resource name

AWS::ECS::AccountSetting

### Description

It is possible to configure ECS Account Settings using the API & GUI:

- https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_PutAccountSetting.html
- https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_PutAccountSettingDefault.html
- https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_DeleteAccountSetting.html
- https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_ListAccountSettings.html

But currently nothing like `AWS::ECS::AccountSetting` exists in CloudFormation.

### Other Details

See `AWS::SSM::ServiceSetting`, it is already possible for another AWS Service to configure Account configurations through CloudFormation, so this should be considered tech debt of AWS since it is missing for `AWS::ECS::AccountSetting`.

Start with the linked ECS account-setting API documentation and compare the requested behavior with AWS::SSM::ServiceSetting. Determine the resource shape and coverage needed for the four listed APIs; done means AWS::ECS::AccountSetting can configure and manage the documented ECS account settings through CloudFormation.

Written by the indexing model from the issue text.