Support AWS DMS Pre-Migration Assessment reports via CloudFormation

### Name of the resource

AWS::DMS::ReplicationTask

### Resource name

_No response_

### Description

There is no way to create Pre-Migration assessment via CFN.

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/AWS_DMS.html

This can be done via CLI and APIs

https://docs.aws.amazon.com/dms/latest/APIReference/API_StartReplicationTaskAssessmentRun.html

https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Tasks.AssessmentReport1.html#CHAP_Tasks.AssessmentReport1.AssessmentRun

Customers who create/manage AWS DMS tasks/replication instances via CFN would also want run pre-migration via CFN, which currently is not possible.

### Other Details

_No response_

Start with the AWS::DMS::ReplicationTask resource in the AWS CloudFormation DMS documentation, then read the StartReplicationTaskAssessmentRun API reference and assessment-report guide. Confirm the CloudFormation-facing behavior and define done as being able to create a pre-migration assessment through CloudFormation, with the resulting report accessible as documented.

Written by the indexing model from the issue text.