fix(autoscaling): cooldown cannot be set with step scaling actions (#30150)

### Issue # (if applicable)

Closes #29779 

### Reason for this change

`cooldown` cannot be set on step scaling and can cause deployment failure in certain regions.

### Description of changes

Deprecate the property and ignore the value. Give a warning.

### Description of how you validated changes

Unit test added.

### Checklist
- [ ] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: GavinZZ