chore(appconfig): update AWS AppConfig Lambda extension layer ARNs

[dzchen22]

• Update all lambda layer version ARNs to latest versions
• Add support for new regions: ap-southeast-6, ap-southeast-7, ca-west-1, ap-east-2, mx-central-1, us-northeast-1
• Add eusc-de-east-1 region support
• Add us-gov-east-1 and us-gov-west-1 ARM64 support
• Remove ISO partition regions (us-isob-, us-isof-, eu-isoe-, us-iso-)
• Update corresponding unit tests

Total regions supported: 40 (both x86_64 and ARM64 platforms)

Issue # (if applicable)

Closes #.

Reason for this change

• Updating lambda extension arns for AppConfig

Description of changes

What code changes did you make?

• Pulled new lambda extension arns and updated them in code
  Why do these changes address the issue?
• Customers are getting outdated arns. New regions also need to be added to the map.
  What alternatives did you consider and reject?
• N/A
  What design decisions have you made?
• N/A

Describe any new or updated permissions being added

Description of how you validated changes

Have you added any unit tests and/or integration tests? Did you test by hand?

• Edited tests that relied on a specific arn version to be returned.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

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