Pseudo parameter for account email

### Name of the resource

Other

### Resource name

AWS::AccountEmail

### Description

There are some use cases where knowing the account email would be helpful, for example when creating a [cost anomaly subscription](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-ce-anomalysubscription-subscriber.html).

The absence of a pseudo parameter means one has to add a parameter to the template, and although the parameter can have an `AllowedPattern` to ensure the value is correct, it's still prone to human error.

Having `AWS::AccountEmail` return the account's email address would help here. It would operate similar to [`AWS::AccountId`](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html#cfn-pseudo-param-accountid).

### Other Details

_No response_

Start by reviewing the AWS::AccountId entry in the linked CloudFormation pseudo-parameter reference and the cost anomaly subscription documentation. Confirm the proposed AWS::AccountEmail behavior and its constraints, then determine what CloudFormation coverage or design work is needed; done means the pseudo parameter is supported and documented for templates.

Written by the indexing model from the issue text.