chore(synthetics): selenium 7.0 runtime (#35748)

### Reason for this change
https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/CloudWatch_Synthetics_Library_python_selenium.html#CloudWatch_Synthetics_runtimeversion-syn-python-selenium-7.0

### Description of changes
- Synthetics add selenium 7.0 runtime

### 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