AWS::GlobalAccelerator: Allow creating cross-account attachments

### Describe the feature

Cross-account attachments specify principals who have permission to work with resources in accelerators in their own account. See https://docs.aws.amazon.com/global-accelerator/latest/dg/cross-account-resources.html for details.

### Use Case

I work on a central deployment platform where services are deployed into central AWS accounts, and users want to be able to have their own global accelerator endpoints and connect those to the services in the central accounts.

### Proposed Solution

CloudFormation released support for this recently through the `AWS::GlobalAccelerator::CrossAccountAttachment` resource. https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-globalaccelerator-crossaccountattachment.html

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.1055.0

### Environment details (OS name and version, etc.)

nodejs20.x lambda runtime

Start by reading the AWS documentation for AWS::GlobalAccelerator::CrossAccountAttachment and the linked cross-account resources guide, then locate the AWS CDK GlobalAccelerator implementation and its tests. Done means the CDK supports defining and deploying this resource with the documented cross-account principals and includes coverage for the new construct behavior.

Written by the indexing model from the issue text.