fix(cloudwatch-actions): lambda permission use unique prefix id (#34269)

### Issue # (if applicable)

Closes #33958

### Reason for this change
Duplicate id of alarm of multiple StepScalingPolicy

### Description of changes
Update Lambda permission prefix to use `Names.uniqueId`

Considering this requires resource destruction, please let me know if i need a feature flag for the fix. As there was another feature flag in the exact same place.

### Description of how you validated changes
Unit + Integ

### Checklist
- [x] 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)

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

Author: phuhung273