AWS::RDS::DBCluster - add WithExpressConfiguration property

### Name of the resource

AWS::RDS::DBCluster

### Resource name

_No response_

### Description

The [AWS::RDS::DBCluster](https://docs.aws.amazon.com/ja_jp/AWSCloudFormation/latest/TemplateReference/aws-resource-rds-dbcluster.html) resource type in CloudFormation does not support "WithExpressConfiguration" property (Specifies to create an Aurora DB Cluster with express configuration in seconds).

- Blog post: https://aws.amazon.com/blogs/aws/announcing-amazon-aurora-postgresql-serverless-database-creation-in-seconds/
- Docs: https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/CHAP_GettingStartedAurora.AuroraPostgreSQL.ExpressConfig.html
- API Docs: https://docs.aws.amazon.com/AmazonRDS/latest/APIReference/API_CreateDBCluster.html#API_CreateDBCluster_RequestParameters

### Other Details

_No response_

Start with the AWS::RDS::DBCluster resource coverage in this repository, then compare its supported properties with the CreateDBCluster API documentation linked in the issue. Confirm the expected behavior and validation for WithExpressConfiguration using the linked CloudFormation and Aurora documentation, and verify the property is covered by the repository's relevant checks before considering the issue done.

Written by the indexing model from the issue text.