Fix: update CloudFrontKeyValueStore client to use AWS4aSignerCRTWrapper

[muhammad-othman]

Description

CloudFrontKeyValueStore latest version requires SigV4a, however our code is still using SigV4 because C2J still has Sigv4 as the SignatureVersion.
This PR forces CloudFrontKeyValueStore client to use AWS4aSignerCRTWrapper till we get SRA identity and auth in place.

Motivation and Context

A customer raised this issue #3143 when using CloudFrontKeyValueStore

Testing

• Tested the same code that was included in the issue and ListKeysAsync method returned the keys and didn't throw an exception.
• Did a full dry run

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My code follows the code style of this project
• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have read the README document
• I have added tests to cover my changes
• All new and existing tests passed

License

• I confirm that this pull request can be released under the Apache 2 license

[normj]

Approve pending internal checks pass.