DeregisterScalableTarget for ApplicationAutoScaling

### Name of the resource

AWS::ApplicationAutoScaling::ScalableTarget

### Resource name

_No response_

### Description

**Describe the feature**
CDK implementation to Deregister an Application Auto Scaling scalable target after it is finished using it.
A CloudFormation L1 Construct would be great as well for starters.

**Use Case**
I am creating sagemaker endpoint and attaching autoscaling policy using scalable targets. During update of that endpoint stack I need to be able to deregister target from that endpoint.

Create a FR with CDK but they suggested to have an implementation from CloudFormation initially.
https://github.com/aws/aws-cdk/issues/29626

### Other Details

_No response_

Start by reviewing the requested AWS::ApplicationAutoScaling::ScalableTarget resource behavior and the linked AWS CDK issue 29626. Confirm how deregistration should work during a stack update and whether a CloudFormation L1 construct is the intended first deliverable; done means the resource supports the requested deregistration operation.

Written by the indexing model from the issue text.