WaitCondition does not support deletes

### Name of the resource

AWS::CloudFormation::WaitCondition

### Resource name

No response

### Description

I have a situation where I need to wait for long running deletes and the WaitCondition is deleted before receiving the signal back.
In SageMaker Studio domain, when user connects to notebooks environment, it spins-up new compute resource applications hosting the notebooks. These apps created outside IaC must be deleted first, in order to delete the SageMaker Studio domain user created by CDK/CloudFormation.
One problem is that deleting an app can take up to 20 minutes so it is too long for a simple Lambda Function based Custom Resource.
The other is that even when deploying a StepFunction in a different stack to monitor the deletion of the SageMaker Studio domain user apps and use that StepFunction to return a signal to the WaitCondition once all apps are deleted, CloudFormation deletes the WaitCondition, WaitConditionHandle and CustomResource before receiving the signal from the StepFunction, and then moves on to try to delete the SageMaker Sutdio domain User.
There are cases were we need a mechanism to wait for outside-of-stack resource deletion the same way we can wait for resource creation.

### Other Details

No response

Start by reviewing the CloudFormation AWS::CloudFormation::WaitCondition and WaitConditionHandle behavior during stack deletion, along with the described CustomResource and StepFunction flow. Confirm the lifecycle problem with a long-running SageMaker Studio app deletion scenario. Done means the required deletion-wait behavior is clearly specified and covered for the outside-of-stack resource case.

Written by the indexing model from the issue text.